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Beaver J, Goldberg SE, Edgley A, Harwood RH. 'Socialised care futility' in the care of older people in hospital who call out repetitively: An ethnographic study. Int J Nurs Stud 2020; 107:103589. [PMID: 32446017 DOI: 10.1016/j.ijnurstu.2020.103589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 03/24/2020] [Accepted: 03/29/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND People living with dementia may call out repetitively, sometimes called disruptive vocalisation, or verbal agitation. In literature and policy, patients who call out repetitively are assumed to be expressing an unmet need, which should be met. Yet there has been little systematic study of this patient group in an acute hospital setting. OBJECTIVES To better understand patients who call out repetitively and to identify what care looks like in an acute hospital setting. DESIGN Ethnography. SETTINGS Ten acute geriatric medical wards in two hospitals. PARTICIPANTS 30 cognitively impaired patients who were calling out repetitively, and 15 members of hospital staff. METHODS Semi-structured interviews with hospital staff, 150 h of ward observations and informal conversations with staff, scrutiny of medical and nursing documentation, and measures of patient health status. RESULTS Patients who called out were moderately or severely cognitively impaired, often had delirium, were very physically disabled, and many were approaching the end of life. Most hospital staff were found to hold contradictory views: that calling out represents distress or unmet need, but that nothing can be done to alleviate the calling out. During informal conversations, most staff also tended to say that they intuitively recognised when intervening was likely to alleviate calling out. During observations, many staff appeared to and spoke of the ability to 'block' calling out. As a result we argue that social, emotional and physical needs may get overlooked. We argue that some calling out is due to a need that is unmeetable. We also found that while staff would talk about strategies for identifying need, observations and hospital documentation did not support evidence of systematic attempts to identify potential need. CONCLUSION Calling out repetitively within a hospital setting is difficult for staff to understand and to respond to. This is because many of these patients are severely cognitively impaired, often immobile and dependent on their professional carers. We argue that a form of socialised care futility is communicated between staff and is used to rationalise becoming unresponsive to calling-out. We explain this phenomenon as resulting from two protective mechanisms: defence of staff's professional identity as competent practitioners; and defence of staff as having personal morality. Socialised care futility risks good quality care, therefore systematic strategies to assess and manage possible need should be developed, even if calling out remains irresolvable in some cases.
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Affiliation(s)
- J Beaver
- School of Health Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2RD, United Kingdom. https://twitter.com/Jessica_Beaver
| | - S E Goldberg
- School of Health Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2RD, United Kingdom. https://twitter.com/se_goldberg
| | - A Edgley
- School of Health Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2RD, United Kingdom
| | - R H Harwood
- School of Health Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2RD, United Kingdom. https://twitter.com/RowanHarwood
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Swieboda D, Beaver J, Johnson EL, Skountzou I, Chakraborty R. Baby’s First Macrophage: characterizing Hofbauer Cell phenotype through gestation using unsupervised dimensionality reduction. The Journal of Immunology 2020. [DOI: 10.4049/jimmunol.204.supp.235.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Fetal placental macrophages (Hofbauer cells (HCs)) appear at 18 days post-conception and are maintained throughout pregnancy. Despite their identification more than a century ago, there are few studies characterizing the evolution of human HC phenotype through gestation. Using high-dimensional flow cytometry, we measured expression of CD68, CD80, CD86, HLA-DR, CD163, CD206, and CD209 on human HCs ex vivo. This panel includes markers previously validated on term human HCs for immune activation (CD80, CD86) and modulation (DC-SIGN, HLA-DR). To best capture the spectrum of HC diversity across gestation, we employed an unbiased approach to analyze processed datasets from HCs isolated from placentae 12–17 weeks gestational age (n=5), 17–24 weeks gestational age (n=7) and at term (n=5) using t-distributed stochastic neighbor embedding analysis (tSNE). HC populations were more diverse early in pregnancy and at term, compared to the second trimester; this is anticipated given the changing microenvironment following initial placental anchoring to eventual parturition. Marker expression heatmaps were generated to assess gestation-dependent changes in HC phenotype; HCs expressing activation markers were most frequent in early gestation, and reduced by term. HCs bearing markers of immune modulation were most frequent at mid-gestation, and least in early gestation. These results demonstrate the power of utilizing computational methods to analyze high-dimensional flow cytometry data collected from an understudied cell type and demonstrate how HCs phenotypically evolve during human pregnancy.
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Swieboda D, Johnson EL, Beaver J, Haddad L, Enninga EAL, Hathcock M, Cordes S, Jean V, Lane I, Skountzou I, Chakraborty R. Baby's First Macrophage: Temporal Regulation of Hofbauer Cell Phenotype Influences Ligand-Mediated Innate Immune Responses across Gestation. J Immunol 2020; 204:2380-2391. [PMID: 32213562 DOI: 10.4049/jimmunol.1901185] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 02/21/2020] [Indexed: 12/20/2022]
Abstract
The importance of fetal placental macrophages (Hofbauer cell [HCs]) is underscored by their appearance 18 d postconception and maintenance through term; however, how human HCs evolve during healthy pregnancy and how microenvironment and ontogeny impact phenotype and function remain unknown. In this study, we comprehensively classify human HCs ex vivo, interrogate phenotypic plasticity, and characterize antiviral immune responses through gestation. Activated HCs were abundant in early pregnancy and decreased by term; molecular signatures emphasize inflammatory phenotypes early in gestation. Frequency of HCs with regulatory phenotypes remained high through term. Furthermore, term HCs exhibited blunted responses to stimulation, indicating reduced plasticity. IFN-λ1 is a key placental IFN that appeared less protective than IFN-α, suggesting a potential weakness in antiviral immunity. Ligand-specific responses were temporally regulated: we noted an absence of inflammatory mediators and reduced antiviral gene transcription following RIG-I activation at term despite all HCs producing inflammatory mediators following IFN-γ plus LPS stimulation. Collectively, we demonstrate sequential, evolving immunity as part of the natural history of HCs through gestation.
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Affiliation(s)
- Dominika Swieboda
- Department of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA 30322.,Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Erica L Johnson
- Department of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA 30322
| | - Jacob Beaver
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Lisa Haddad
- Department of Gynecology and Obstetrics, Emory University School of Medicine, Atlanta, GA 30322
| | - Elizabeth Ann L Enninga
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Mayo Clinic, Alix School of Medicine, Rochester, MN 55905
| | - Matthew Hathcock
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Alix School of Medicine, Rochester, MN 55905; and
| | - Sarah Cordes
- Department of Gynecology and Obstetrics, Emory University School of Medicine, Atlanta, GA 30322
| | - Valerie Jean
- Department of Gynecology and Obstetrics, Emory University School of Medicine, Atlanta, GA 30322
| | - Ivy Lane
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Ioanna Skountzou
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
| | - Rana Chakraborty
- Department of Pediatrics, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA 30322; .,Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Mayo Clinic, Alix School of Medicine, Rochester, MN 55905.,Division of Infectious Diseases, Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Alix School of Medicine, Rochester, MN 55905
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4
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Hooker B, Tobon G, Baker S, Zhu C, Hesterman J, Schmidt K, Rajagovindan R, Chandran P, Joshi S, Bannon A, Hoppin J, Beaver J, Fox G, Day M, Upadhyay J. Gabapentin-induced pharmacodynamic effects in the spinal nerve ligation model of neuropathic pain. Eur J Pain 2013; 18:223-37. [DOI: 10.1002/j.1532-2149.2013.00364.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2013] [Indexed: 12/15/2022]
Affiliation(s)
- B.A. Hooker
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
| | | | - S.J. Baker
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
| | - C. Zhu
- Neuroscience Discovery; Abbvie Inc.; North Chicago USA
| | | | | | - R. Rajagovindan
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
| | - P. Chandran
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
| | - S.K. Joshi
- Neuroscience Discovery; Abbvie Inc.; North Chicago USA
| | - A.W. Bannon
- Neuroscience Discovery; Abbvie Inc.; North Chicago USA
| | | | - J. Beaver
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
| | - G.B. Fox
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
| | - M. Day
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
| | - J. Upadhyay
- Integrated Science and Technology; Abbvie Inc.; North Chicago USA
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Abstract
Pneumopericardium occurred after laparoscopic cholecystectomy in a 57-year-old woman. The patient had chest pain accompanied by T-wave inversion on electrocardiogram, with signs and symptoms suggestive of acute myocardial ischemia. Evaluation for myocardial infarction, however, was negative and clinical findings resolved spontaneously. Although pneumopericardium after laparoscopic procedures has been previously reported, this case illustrates how associated findings may mimic those of acute myocardial ischemia or infarction.
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Affiliation(s)
- J Beaver
- Department of Surgery, University of South Alabama, Mobile, USA
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Waring P, Lambert D, Sjaarda A, Hurne A, Beaver J. Increased cell surface exposure of phosphatidylserine on propidium iodide negative thymocytes undergoing death by necrosis. Cell Death Differ 1999; 6:624-37. [PMID: 10453073 DOI: 10.1038/sj.cdd.4400540] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Phosphatidylserine (PS) exposure on propidium iodide negative cells using FITC labelled annexin-V has been used to quantify apoptosis in vitro and in vivo. Detection of PS within cells undergoing necrosis is also possible if labelled annexin-V specific for PS enters the cell following early membrane damage. Necrotic or late apoptotic cells can be excluded from flow cytometric analysis using propidium iodide which enters and stains cells with compromised membrane integrity. Here we show that thymocytes undergoing death exclusively by necrosis show early exposure of PS prior to loss of membrane integrity. This early exposure of PS occurs in cells treated with agents which both raise intracellular calcium levels and are also capable of interacting with protein thiol groups. We also demonstrate that PS exposure in thymocytes induced to undergo apoptosis by three different agents does not correlate with calcium rises but correlates with and precedes DNA fragmentation.
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Affiliation(s)
- P Waring
- Division of Immunology and Cell Biology, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra, Australia.
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Abstract
1. Gliotoxin belongs to the epipolythiodioxopiperazine class of secondary metabolites. These compounds show a diverse range of biological activity including antimicrobial, antifungal and antiviral properties. They also display potent in vitro and in vivo immunomodulating activity. 2. Their properties resulted in a number of early studies designed to exploit their possible chemotherapeutic value, although the general toxicity of most members of this class has precluded clinical use. 3. Most recently, their selective immunosuppressive properties have led to the possibility of ex vivo treatment of tissue to selectively remove immune cells responsible for tissue rejection. The mode of action of gliotoxin appears to be via covalent interaction to proteins through mixed disulphide formation and gliotoxin has been shown to inhibit a number of thiol requiring enzymes. 4. Gliotoxin is also a potent inducer of apoptotic cell death in a number of cells. Gliotoxin and other members of this class of toxins may be produced in vivo during the course of fungal infections and contribute to the aetiology of the disease.
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Affiliation(s)
- P Waring
- Division of Cell Biology, John Curtin School, Canberra City, Australia.
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8
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Willsher PC, Beaver J, Pinder S, Bell JA, Ellis IO, Blamey RW, Robertson JF. Prognostic significance of serum c-erbB-2 protein in breast cancer patients. Breast Cancer Res Treat 1996; 40:251-5. [PMID: 8883967 DOI: 10.1007/bf01806813] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The tissue expression of c-erbB-2 protein in breast cancer is a marker of poor prognosis in a number of studies. More recently it has also been suggested that c-erbB-2 expression may predict response to systemic therapy in patients with advanced breast cancer. The measurement of c-erbB-2 protein in the serum of breast cancer patients has now been reported, but the significance of this finding is not clear. In this study an ELISA assay was used to measure c-erbB-2 in the sera of 23 normal controls, 46 benign breast disease patients, and 119 breast cancer patients. Elevated serum c-erbB-2 protein levels were detected in 13% (3/23) of normal controls, 15% (7/46) of benign disease patients, 15% (7/46) of Stage I/II patients, 26% (9/35) of Stage III patients, and 21% (8/38) of Stage IV patients. The tissue expression of the c-erbB-2 protein showed no association with detection of the serum c-erbB-2 protein (p = 0.31). In the 67 Stage III and IV patients who had assessable disease the presence of the c-erbB-2 protein in the serum bore no relationship to response to hormonal therapy (p = 0.71). Serum detection of the c-erbB-2 protein in Stage I/II patients predicted for a worsening of both survival outcome (p = 0.002) and disease free interval (p = 0.002). A worse outcome was also seen for the Stage III patients (p = 0.04) and Stage IV patients, although the latter did not reach statistical significance (p = 0.27). This study found that the presence of c-erbB-2 in the serum of breast cancer patients was of prognostic significance for all stages of disease.
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Affiliation(s)
- P C Willsher
- Professorial Department of Surgery, City Hospital, Nottingham, UK
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9
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Waring P, Beaver J. Cyclosporin A rescues thymocytes from apoptosis induced by very low concentrations of thapsigargin: effects on mitochondrial function. Exp Cell Res 1996; 227:264-76. [PMID: 8831565 DOI: 10.1006/excr.1996.0276] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Raising intracellular calcium levels can induce apoptosis or programmed cell death in many cells. While early rises in intracellular calcium are not universally associated with apoptotic cell death, calcium clearly plays a key role in many of the biochemical events which occur during apoptosis. In this paper we have determined intracellular calcium rises induced by 2, 10, and 100 nM thapsigargin in mouse thymocytes. These concentrations cause increases in cytosolic calcium of 100-250, 400-600, and > 1000 nM, respectively. These rises are sustained for at least 85 min and the ratio between the maximum rise caused by 10 nM compared to 2 nM thapsigargin is 2.1 +/- 0.4 (n = 6). Both 2 and 10 nM thapsigargin cause apoptosis at 24 h as shown by DNA fragmentation and morphology when examined by electron microscopy. Cyclosporin A (CsA) inhibits apoptosis caused by 2 nM thapsigargin but not that caused by 10 nM thapsigargin. Electron microscopy of thymocytes treated with 2 nM thapsigargin at 24 h shows intact mitochondria although with altered morphology. There is no loss of ATP or decrease in the ATP/ADP ratio in these cells over 12 h. Mitochondria in cells treated with 10 nM thapsigargin, however, are swollen by 6 h and many are lost by 24 h. These cells show greatly diminished ATP content by 12 h and a decrease in ATP/ADP ratio. Examination of the effects of PMA, an activator of the plasma membrane calcium ATPase pump, on cells treated with 10 nM thapsigargin suggests that two pools of calcium may be responsible for the differential effects of the two calcium levels in the cells. Probing of the mitochondrial membrane potential (MMP) by rhodamine 123 staining of live cells shows that the collapse of the MMP caused by 10 nM thapsigargin is unaffected by CsA. The MMP is also reduced in cells treated with 2 nM thapsigargin but this is restored by CsA. Cells are also rescued from apoptosis caused by 2 nM thapsigargin by incubation with FK506. This immunosuppressive agent has no effect on the membrane permeability transition induced in isolated mitochondria. These results suggest that very low rises in intracellular calcium in thymocytes cause activation-induced cell death inhibited by CsA and FK506 and are without effect on ATP levels and therefore do not involve irreversible mitochondrial damage. Exceeding these calcium levels by only two-fold results in apoptosis accompanied by reduced ATP levels and mitochondrial damage, although apoptotic cell death in this instance is unaffected by the classic inhibitor of mitochondrial permeability transition, CsA.
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Affiliation(s)
- P Waring
- John Curtin School of Medical Research, Canberra City, ACT, Australia.
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10
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Abstract
Gliotoxin is a secondary metabolite produced by several pathogenic fungi. It has potential clinical applications as an immunosuppressive agent in preventing allograft rejection. At low doses (< 30 nM) gliotoxin displays co-mitogenic activity, but at higher doses induces apoptosis in cells. Here we demonstrate that gliotoxin, although not mitogenic in its own right, enhances activation in preactivated splenocytes by a calcium-independent mechanism. The enhancement in activation correlates with a decrease in intracellular cyclic AMP levels. This property is inhibited by dibutyryl-cAMP. Increasing the concentration of gliotoxin to levels that caused apoptosis produced a dose-related increase in cAMP levels. Thus, the effects of gliotoxin on cell activation and the induction of apoptosis may both be mediated by changed levels of cAMP.
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Affiliation(s)
- P Sutton
- Division of Cell Biology, John Curtin School of Medical Research, Australian National University, Canberra ACT, Australia
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Willsher PC, Beaver J, Blamey RW, Robertson JF. Serum tissue polypeptide specific antigen (TPS) in breast cancer patients: comparison with CA 15.3 and CEA. Anticancer Res 1995; 15:1609-11. [PMID: 7654057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Pre-treatment TPS serum levels from patients with Stage IV breast cancer (n = 66) (1386.0 +/- 3504.5) were significantly higher (p < 0.0001), than normal controls (n = 47), (75.5 +/- 111.5 U/L), benign breast disease patients (n = 84) (58.5 +/ 57.1 U/L), and breast cancer patients with Stage I/II (n = 79) (52.7 +I- 49.5U/L) or Stage III disease (n = 57) (166.7 +/- 218.8). Analysis of sequentially obtained samples from Stage IV patients during endocrine treatment showed TPS alone or in combination with CEA and CA 15.3 was less accurate in predicting response than the combination of CEA with CA 15.3. In this study TPS did not usefully add to the established marker combination of CEA and CA 15.3.
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Affiliation(s)
- P C Willsher
- Professorial Department of Surgery, City Hospital, Nottingham, U.K
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Robertson J, Beaver J, Pearson D, Gilmore A, Willsher P, O'Neill K, McKenna P. 16 TPS in breast cancer. Breast 1995. [DOI: 10.1016/0960-9776(95)90048-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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13
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Wallace DH, Baudoin JP, Beaver J, Coyne DP, Halseth DE, Masaya PN, Munger HM, Myers JR, Silbernagel M, Yourstone KS, Zobel RW. Improving efficiency of breeding for higher crop yield. Theor Appl Genet 1993; 86:27-40. [PMID: 24193380 DOI: 10.1007/bf00223805] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/1991] [Accepted: 05/07/1992] [Indexed: 05/13/2023]
Abstract
Exclusive selection for yield raises, the harvest index of self-pollinated crops with little or no gain in total bipmass. In addition to selection for yield, it is suggested that efficient breeding for higher yield requires simultaneous selection for yield's three major, genetically controlled physiological components. The following are needed: (1) a superior rate of biomass accumulation. (2) a superior rate of actual yield accumulation in order to acquire a high harvest index, and (3) a time to harvest maturity that is neither shorter nor longer than the duration of the growing season. That duration is provided by the environment, which is the fourth major determinant of yield. Simultaneous selection is required because genetically established interconnections among the three major physiological components cause: (a) a correlation between the harvest index and days to maturity that is usually negative; (b) a correlation between the harvest index and total biomass that is often negative, and (c) a correlation between biomass and days to maturity that is usually positive. All three physiological components and the correlations among them can be quantified by yield system analysis (YSA) of yield trials. An additive main effects and multiplicative interaction (AMMI) statistical analysis can separate and quantify the genotype × environment interaction (G × E) effect on yield and on each physiological component that is caused by each genotype and by the different environment of each yield trial. The use of yield trials to select parents which have the highest rates of accumulation of both biomass and yield, in addition to selecting for the G × E that is specifically adapted to the site can accelerate advance toward the highest potential yield at each geographical site. Higher yield for many sites will raise average regional yield. Higher yield for multiple regions and continents will raise average yield on a world-wide basis. Genetic and physiological bases for lack of indirect selection for biomass from exclusive selection for yield are explained.
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Affiliation(s)
- D H Wallace
- Department of Plant Breeding and Biometry, Cornell University, 14853, Ithaca, NY, USA
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Brownie S, Beaver J. Proud of its involvement: Manawatu Polytechnic's role in the development of care-giver courses. N Z Nurs J 1991; 84:22-3. [PMID: 1762717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Beaver J, Hutcheson R, Gateley KW. Results of 1990 immunization survey of 24-month-old children. J Tenn Med Assoc 1991; 84:388-9. [PMID: 1921380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- J Beaver
- Communicable Disease Control Section, Tennessee Department of Health, Nashville
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16
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Beaver J, Gateley KW, Hutcheson R. Results of immunization surveys. J Tenn Med Assoc 1990; 83:192-3, 195. [PMID: 2332979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- J Beaver
- Tennessee Department of Health and Environment, Nashville
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Allegra CJ, Boarman D, Kovacs JA, Morrison P, Beaver J, Chabner BA, Masur H. Interaction of sulfonamide and sulfone compounds with Toxoplasma gondii dihydropteroate synthase. J Clin Invest 1990; 85:371-9. [PMID: 2298911 PMCID: PMC296434 DOI: 10.1172/jci114448] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Toxoplasma gondii is a common protozoan disease that often causes life-threatening disease, particularly among patients with the acquired immunodeficiency syndrome. This study demonstrates that the dihydropteroate synthase in T. gondii is kinetically distinct from the enzyme characterized from other sources and can be highly purified with a high yield using sequential dye-affinity chromatography. Conditions have been identified that allow for stabilization of the purified enzyme, and its physical characteristics have been elucidated. The molecular weight of the native protein was 125,000 and the protein appeared to contain both dihydropteroate synthase and 6-hydroxymethyl-dihydropterin pyrophosphokinase activities. The sulfonamide class of compounds vary in inhibitory potency by more than three orders of magnitude. Sulfathiazole, sulfamethoxazole, and sulfamethazine, with 50% inhibitory concentrations (IC50's) of 1.7, 2.7, and 5.7 microM, respectively, represent the most potent of this class of inhibitors. Several sulfone analogues, including dapsone, were identified as highly potent inhibitors with IC50's less than 1 microM. The results of these cell-free experiments were corroborated by investigating the metabolic inhibition produced by the various inhibitors in intact organisms. The qualitative and quantitative relations among the inhibitors were preserved in both the cell-free and intact cell assay systems. These studies suggest that the sulfones may be important therapeutic agents for the treatment of toxoplasmosis.
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Affiliation(s)
- C J Allegra
- Medicine Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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18
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Kovacs JA, Allegra CJ, Beaver J, Boarman D, Lewis M, Parrillo JE, Chabner B, Masur H. Characterization of de novo folate synthesis in Pneumocystis carinii and Toxoplasma gondii: potential for screening therapeutic agents. J Infect Dis 1989; 160:312-20. [PMID: 2527275 DOI: 10.1093/infdis/160.2.312] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Drug therapy studies imply that Pneumocystis carinii and Toxoplasma gondii possess the enzymes necessary for de novo folate synthesis. To verify this, incorporation of [3H]paraaminobenzoic acid [( 3H]PABA) into reduced folates by P. carinii and T. gondii was investigated. Both organisms synthesized tritiated reduced folates. In P. carinii, 10-formyltetrahydrofolate and tetrahydrofolate, and in T. gondii, 5-formyltetrahydrofolate were the major synthesized folates. P. carinii remained metabolically active in vitro for only a few days. Because current systems for screening antipneumocystis agents are cumbersome, the utility of this assay system for screening therapeutic agents was investigated. Sulfonamides and pentamidine efficiently inhibited de novo folate synthesis in P. carinii. Inhibitors of dihydrofolate reductase such as trimethoprim and trimetrexate were poor inhibitors for P. carinii but efficient inhibitors for T. gondii. This study demonstrates the first unambiguous evidence of metabolic activity in P. carinii, and provides a potential assay for efficiently screening antipneumocystis drugs in vitro.
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Affiliation(s)
- J A Kovacs
- Critical Care Medicine Department, National Institutes of Health, Bethesda, Maryland 20892
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Rasaiah B, Otero JG, Russell IJ, Butler-Jones DA, Prescott JF, West MM, Maxwell BE, Beaver J. Pasteurella multocida septicemia during pregnancy. CMAJ 1986; 135:1369-72. [PMID: 3779573 PMCID: PMC1491666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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