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Abstract
AIMS Chronic loneliness is experienced by around a third of parents, but there is no comprehensive review into how, why and which parents experience loneliness. This scoping review aimed to provide insight into what is already known about parental loneliness and give directions for further applied and methodological research. METHODS Searches for peer-reviewed articles were undertaken in six databases: PsycINFO, Medline, CINAHL, Embase, Web of Science and Scopus, during May 2019 to February 2020. We searched for English studies which examined loneliness experienced during parenthood, including studies that involved parents with children under 16 years and living at home and excluding studies on pregnancy, childbirth or postbirth hospital care. RESULTS From 2566 studies retrieved, 133 were included for analysis. Most studies (n = 80) examined the experience of loneliness in specific groups of parents, for example, teenage parents, parents of a disabled child. Other studies examined theoretical issues (n = 6) or health and wellbeing impacts on parents (n = 16) and their offspring (n = 17). There were 14 intervention studies with parents that measured loneliness as an outcome. Insights indicate that parental loneliness may be different to loneliness experienced in other cohorts. There is evidence that parental loneliness has direct and intergenerational impacts on parent and child mental health. Some parents (e.g. with children with chronic illness or disability, immigrant or ethnic minority parents) also appear to be at increased risk of loneliness although evidence is not conclusive. CONCLUSION This work has identified key gaps with further international, comparative and conceptual research needed.
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Affiliation(s)
- R Nowland
- School of Community Health and Midwifery, University of Central Lancashire Brooke Building, Preston PR2 1HE, UK
| | - G Thomson
- University of Central Lancashire, Preston, UK
| | - L McNally
- University of Central Lancashire, Preston, UK
| | - T Smith
- University of Central Lancashire, Preston, UK
| | - K Whittaker
- University of Central Lancashire, Preston, UK
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2
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Govindarajan AF, Cooney L, Whittaker K, Bloch D, Burdorf RM, Canning S, Carter C, Cellan SM, Eriksson FAA, Freyer H, Huston G, Hutchinson S, McKeegan K, Malpani M, Merkle-Raymond A, Ouellette K, Petersen-Rockney R, Schultz M, Siuda ANS. The distribution and mitochondrial genotype of the hydroid Aglaophenia latecarinata is correlated with its pelagic Sargassum substrate type in the tropical and subtropical western Atlantic Ocean. PeerJ 2019; 7:e7814. [PMID: 31637119 PMCID: PMC6802585 DOI: 10.7717/peerj.7814] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 09/02/2019] [Indexed: 11/20/2022] Open
Abstract
The pelagic brown macroalga Sargassum supports rich biological communities in the tropical and subtropical Atlantic region, including a variety of epiphytic invertebrates that grow on the Sargassum itself. The thecate hydroid Aglaophenia latecarinata is commonly found growing on some, but not all, Sargassum forms. In this study, we examined the relationship between A. latecarinata and its pelagic Sargassum substrate across a broad geographic area over the course of 4 years (2015–2018). The distribution of the most common Sargassum forms that we observed (Sargassum fluitans III and S. natans VIII) was consistent with the existence of distinct source regions for each. We found that A. latecarinata hydroids were abundant on both S. natans VIII and S. fluitans III, and also noted a rare observation of A. latecarinata on S. natans I. For the hydroids on S. natans VIII and S. fluitans III, hydroid mitochondrial genotype was strongly correlated with the Sargassum substrate form. We found significant population genetic structure in the hydroids, which was also consistent with the distributional patterns of the Sargassum forms. These results suggest that hydroid settlement on the Sargassum occurs in type-specific Sargassum source regions. Hydroid species identification is challenging and cryptic speciation is common in the Aglaopheniidae. Therefore, to confirm our identification of A. latecarinata, we conducted a phylogenetic analysis that showed that while the genus Aglaophenia was not monophyletic, all A. latecarinata haplotypes associated with pelagic Sargassum belonged to the same clade and were likely the same species as previously published sequences from Florida, Central America, and one location in Brazil (São Sebastião). A nominal A. latecarinata sequence from a second Brazilian location (Alagoas) likely belongs to a different species.
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Affiliation(s)
| | | | | | - Dana Bloch
- Sea Education Association, Woods Hole, MA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Amy N S Siuda
- Sea Education Association, Woods Hole, MA, USA.,Marine Science Discipline, Eckerd College, St. Petersburg, FL, USA
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Rutledge T, Kenkre TS, Thompson DV, Bittner VA, Whittaker K, Eastwood JA, Eteiba W, Cornell CE, Krantz DS, Pepine CJ, Johnson BD, Handberg EM, Bairey Merz CN. Psychosocial predictors of long-term mortality among women with suspected myocardial ischemia: the NHLBI-sponsored Women's Ischemia Syndrome Evaluation. J Behav Med 2016; 39:687-93. [PMID: 27017335 DOI: 10.1007/s10865-016-9737-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 03/21/2016] [Indexed: 11/26/2022]
Abstract
This paper evaluated long-term associations between psychosocial factors and premature mortality among women with suspected coronary artery disease (CAD). We tracked total mortality events over a median 9.3 years in a cohort of 517 women [baseline mean age = 58.3 (11.4) years]. Baseline evaluations included coronary angiography, psychosocial testing, and CAD risk factors. Measures included the Spielberger Trait Anxiety Scale, Beck Depression Inventory, self-rated health, and Social Network Index. Cox regression analysis was used to assess relationships. Covariates included age, CAD risk factors, and CAD severity. BDI scores (HR 1.09, 95 % CI 1.02-1.15), STAI scores (HR .86, 95 % CI .78-.93), and very good self-rated health (relative to the poor self-rated health group; HR .33, 95 % CI .12-.96) each independently predicted time to mortality outcomes in the combined model. SNI scores (HR .91, 95 % CI .81-1.06) and other self-rated health categories (i.e., fair, good, and excellent categories) were not significant mortality predictors after adjusting for other psychosocial factors. These results reinforce and extend prior psychosocial research in CAD populations.
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Affiliation(s)
- Thomas Rutledge
- VA San Diego Healthcare System, Psychology Service 116B, 3350 La Jolla Village Drive, San Diego, CA, 92161, USA.
- University of California, San Diego, CA, USA.
| | | | | | - Vera A Bittner
- University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kerry Whittaker
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | | | | | - Carol E Cornell
- University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - David S Krantz
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | | | | | | | - C Noel Bairey Merz
- Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, CA, USA
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4
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Gottlieb SS, Harris K, Todd J, Estis J, Christenson RH, Torres V, Whittaker K, Rebuck H, Wawrzyniak A, Krantz DS. Prognostic significance of active and modified forms of endothelin 1 in patients with heart failure with reduced ejection fraction. Clin Biochem 2014; 48:292-6. [PMID: 25541019 DOI: 10.1016/j.clinbiochem.2014.12.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [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: 09/22/2014] [Revised: 11/26/2014] [Accepted: 12/12/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Concentrations of endothelin I (ET1) are elevated in CHF patients and, like other biomarkers that reflect hemodynamic status and cardiac pathophysiology, are prognostic. The Singulex assay (Sgx-ET1) measures the active form of ET1, with a short in vivo half-life and the Brahms assay measures C-terminal endothelin-1 (CT-ET1), a modified (degraded) product with longer half-life. We aimed to determine the prognostic importance of active and modified forms of endothelin 1 (Singulex and Brahms assays) in comparison with other commonly measured biomarkers of inflammation, hemodynamic status and cardiac physiology in CHF. DESIGN AND METHODS Plasma biomarkers (Sgx-ET1, CT-ET1, NTproBNP, IL-6, TNFα, cTnI, VEGF, hs-CRP, Galectin-3, ST2) were measured in 134 NYHA class II and III CHF patients with systolic dysfunction. Prognostic importance of biomarkers for hospitalization or death were calculated by both logistic regression and Kaplan-Meier survival analyses. RESULTS CT-ET1 (OR=5.2, 95% CI=1.7-15.7) and Sgx-ET1 (OR=2.9, CI=1.1-7.7) were independent predictors of hospitalization and death and additively predicted events after adjusting for age, sex, and other significant biomarkers. Other biomarkers did not improve the model. Similarly, in Cox regression analysis, only CT-ET1 (HR 3.4, 95% CI=1.4-8.4), VEGF (2.7, 95% CI=1.3-5.4), and Sgx-ET1 (HR 2.6, 95% CI=1.2-5.6) were independently prognostic. CONCLUSIONS Elevated concentrations of endothelin 1 predict mortality and hospitalizations in HF patients. Endothelin 1 was more prognostic than commonly obtained hemodynamic, inflammatory, and fibrotic biomarkers. Two different assays of endothelin 1 independently and synergistically were prognostic, suggesting either complementary information or extreme prognostic importance.
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Affiliation(s)
| | - Kristie Harris
- University of Maryland School of Medicine, Baltimore, MD, USA; Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | | | | | | | | | - Kerry Whittaker
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Heather Rebuck
- University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew Wawrzyniak
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - David S Krantz
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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5
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Rutledge T, Kenkre TS, Thompson DV, Bittner VA, Whittaker K, Eastwood JA, Eteiba W, Cornell CE, Krantz DS, Pepine CJ, Johnson BD, Handberg EM, Bairey Merz CN. Depression, dietary habits, and cardiovascular events among women with suspected myocardial ischemia. Am J Med 2014; 127:840-7. [PMID: 24769297 PMCID: PMC4161621 DOI: 10.1016/j.amjmed.2014.04.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 04/03/2014] [Accepted: 04/03/2014] [Indexed: 01/16/2023]
Abstract
BACKGROUND Dietary habits and depression are associated with cardiovascular disease risk. Patients with depression often report poor eating habits, and dietary factors may help explain commonly observed associations between depression and cardiovascular disease. METHODS From 1996 to 2000, 936 women were enrolled in the Women's Ischemia Syndrome Evaluation at 4 US academic medical centers at the time of clinically indicated coronary angiography and then assessed (median follow-up, 5.9 years) for adverse outcomes (cardiovascular disease death, heart failure, myocardial infarction, stroke). Participants completed a protocol including coronary angiography (coronary artery disease severity) and depression assessments (Beck Depression Inventory scores, antidepressant use, and depression treatment history). A subset of 201 women (mean age, 58.5 years; standard deviation, 11.4) further completed the Food Frequency Questionnaire for Adults (1998 Block). We extracted daily fiber intake and daily servings of fruit and vegetables as measures of dietary habits. RESULTS In separate Cox regression models adjusted for age, smoking, and coronary artery disease severity, Beck Depression Inventory scores (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.01-1.10), antidepressant use (HR, 2.4; 95% CI, 1.01-5.9), and a history of treatment for depression (HR, 2.4; 95% CI, 1.1-5.3) were adversely associated with time to cardiovascular disease outcomes. Fiber intake (HR, 0.87; 95% CI, 0.78-0.97) and fruit and vegetable consumption (HR, 0.36; 95% CI, 0.19-0.70) were associated with a decreased time to cardiovascular disease event risk. In models including dietary habits and depression, fiber intake and fruit and vegetable consumption remained associated with time to cardiovascular disease outcomes, whereas depression relationships were reduced by 10% to 20% and nonsignificant. CONCLUSIONS Among women with suspected myocardial ischemia, we observed consistent relationships among depression, dietary habits, and time to cardiovascular disease events. Dietary habits partly explained these relationships. These results suggest that dietary habits should be included in future efforts to identify mechanisms linking depression to cardiovascular disease.
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Affiliation(s)
- Thomas Rutledge
- VA San Diego Healthcare System, San Diego, Calif; University of California, San Diego.
| | | | | | | | - Kerry Whittaker
- Uniformed Services University of the Health Sciences, Bethesda, Md
| | | | | | | | - David S Krantz
- Uniformed Services University of the Health Sciences, Bethesda, Md
| | | | | | | | - C Noel Bairey Merz
- Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, Calif
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Gottlieb SS, Harris K, Todd J, Estis J, Christenson RH, Torres V, Rebuck H, Whittaker K, Wawrzyniak A, Krantz D. Prognostic Significance of Active and Modified Forms of Endothelin 1 in Patients with Heart Failure with Reduced Ejection Fraction. J Card Fail 2014. [DOI: 10.1016/j.cardfail.2014.06.221] [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: 11/17/2022]
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7
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Gottlieb SS, Dilsizian V, Wawrzyniak AJ, Smith M, Harris KM, Whittaker K, Krantz D. Congruity between Mental Stress-Induced and Adenosine-Induced Myocardial Ischemia Assessed Using SPECT in Heart Failure Patients. J Card Fail 2014. [DOI: 10.1016/j.cardfail.2014.06.056] [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: 10/25/2022]
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8
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Bergsland EK, Ko AH, Tempero MA, Whittaker K, Weber T, Fong L, Park JW, Hanahan D, Venook AP. Phase I trial of metronomic cyclophosphamide (CTX), bevacizumab (BV) and imatinib (IM) in patients (pts) with advanced solid tumors. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.15026] [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: 11/20/2022] Open
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9
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Bergsland EK, Ko AH, Tempero MA, Whittaker K, Weber T, Fong L, Park JW, Yeh BM, Hanahan D, Venook AP. Phase 1 trial of metronomic cyclophosphamide (CTX), bevacizumab (BV) and imatinib (IM) in patients (pts) with advanced solid tumors. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.14620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Ollmann M, Young LM, Di Como CJ, Karim F, Belvin M, Robertson S, Whittaker K, Demsky M, Fisher WW, Buchman A, Duyk G, Friedman L, Prives C, Kopczynski C. Drosophila p53 is a structural and functional homolog of the tumor suppressor p53. Cell 2000; 101:91-101. [PMID: 10778859 DOI: 10.1016/s0092-8674(00)80626-1] [Citation(s) in RCA: 330] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The importance of p53 in carcinogenesis stems from its central role in inducing cell cycle arrest or apoptosis in response to cellular stresses. We have identified a Drosophila homolog of p53 ("Dmp53"). Like mammalian p53, Dmp53 binds specifically to human p53 binding sites, and overexpression of Dmp53 induces apoptosis. Importantly, inhibition of Dmp53 function renders cells resistant to X ray-induced apoptosis, suggesting that Dmp53 is required for the apoptotic response to DNA damage. Unlike mammalian p53, Dmp53 appears unable to induce a G1 cell cycle block when overexpressed, and inhibition of Dmp53 activity does not affect X ray-induced cell cycle arrest. These data reveal an ancestral proapoptotic function for p53 and identify Drosophila as an ideal model system for elucidating the p53 apoptotic pathway(s) induced by DNA damage.
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Affiliation(s)
- M Ollmann
- Exelixis, Inc., South San Francisco, California 94080, USA
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Abstract
The purpose of this paper is to present a case study of the perspectives of their role of a group of community lecturer-practitioners and a community teacher, who referred to themselves as 'community facilitators'. A qualitative design was used and data were collected by semi-structured interviews. These were transcribed and content analysis was undertaken. All participants provided a liaison role between the college and the community practitioners, prepared students for their clinical experience and assisted in relating theory to practice. The participants described how they managed the role and how they supported each other. Developing small teams of facilitators may provide a bridge between teachers and practitioners and can serve as a basis for further study of the lecturer-practitioner role.
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Affiliation(s)
- B Shepherd
- School of Nursing, Midwifery & Health Visiting, University of Manchester, UK
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13
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Thomson AM, Davies S, Shepherd B, Whittaker K. Continuing education needs of community nurses, midwives and health visitors for supervising and assessing students. Nurse Educ Today 1999; 19:93-106. [PMID: 10335191 DOI: 10.1054/nedt.1999.0616] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The objective of this study was to ascertain the changing educational needs of community nurses, midwives and health visitors in relation to the teaching, supervising and assessing of pre- and post-registration students. A questionnaire was sent to all education institutions providing community nursing experience in England (Whittaker et al. 1997), which allowed identification of three centres for in-depth study. Questionnaires were sent to practitioners (community nurses and midwives, health visitors and school nurses), their managers, and teachers of community courses in the three centres: 314 were returned. Eight semi-structured interviews were undertaken with volunteers in each of the study centres (n = 24). Extensive demands are being made on community staff to provide learning experiences for students on a wide range of courses. Practitioners reported that in order to fulfil their teaching and assessing functions they needed continuing education in matters which would assist them to provide research-based practice and education, teaching and assessing in the community and personal skills, for example assertiveness and counselling. Less than a quarter of practitioners were undertaking continuing education courses. However, opportunities for further academic study varied enormously and most practitioners had to study in their own time at their own expense.
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Affiliation(s)
- A M Thomson
- School of Nursing, Midwifery & Health Visiting, University of Manchester, UK
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14
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Sakas DE, Whittaker K, Abbasi KH, Zervas NT. Experimental microneurosurgery of the trigeminal nerve: surgical technique for ganglionectomy and rhizotomy in the cat. J Neurosci Methods 1996; 65:137-41. [PMID: 8740590 DOI: 10.1016/0165-0270(95)00129-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [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: 02/01/2023]
Abstract
The techniques of two experimental surgical operations on the trigeminal nerve are described, namely, excision of the trigeminal ganglion (ganglionectomy) and division of the trigeminal root (rhizotomy), in the cat. These techniques have been developed with the specific aims of achieving the trigeminal lesion and also preserving a satisfactory postoperative quality of life for the animal in order to make it possible to study the long-term effects of trigeminal dennervation. To the best of our knowledge, a detailed description of such a surgical methodology is lacking; reporting of these procedures may facilitate future research on the trigeminal nerve.
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15
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Finkelstein R, Ma HD, Ghezzo H, Whittaker K, Fraser RS, Cosio MG. Morphometry of small airways in smokers and its relationship to emphysema type and hyperresponsiveness. Am J Respir Crit Care Med 1995; 152:267-76. [PMID: 7599834 DOI: 10.1164/ajrccm.152.1.7599834] [Citation(s) in RCA: 54] [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: 01/26/2023] Open
Abstract
Based on our previous finding, of increased small airways disease in centrilobular emphysema (CLE) when compared with panlobular emphysema (PLE), we hypothesized that smokers who develop CLE would have increased airway responsiveness associated with airway inflammation and exaggerated airway narrowing, but not smokers with PLE. We compared preoperative methacholine challenge with the morphologic and cellular inflammatory characteristics of the airways in the lungs of six nonsmokers, 10 smokers with CLE, and five smokers with PLE. The airways of the CLE group were narrower than those of the nonsmokers (KS < 0.05) and the PLE group (KS < 0.05), but perimeters were not different. A greater percentage of airways in the CLE group showed infolding of the epithelium and lumen deformity than in the PLE group and nonsmokers (p < 0.05). Airway inner wall thickening (WI) was increased in the CLE group when compared with the PLE group and nonsmokers (p < 0.05), and WI correlated significantly with PC20 in the CLE group (r = -0.64, p < 0.01) but not in the PLE group and nonsmokers. The number of T lymphocytes in the airway walls correlated with PC20 in the CLE group (r = -0.50, p < 0.05) but not in the PLE group. In conclusion, despite similar age, smoking history, and range of airflow limitation, there was a clear difference in the methacholine responsiveness between the emphysema groups, suggesting that responsiveness is not just a reaction to smoking but either a reaction developing in some smokers or an abnormality initially present in some smokers which, in combination with exposure to cigarettes, determines the development of a type of lung disease: CLE.
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Affiliation(s)
- R Finkelstein
- Respiratory Division, Royal Victoria Hospital, Meakins Christie Laboratories, McGill University, Montreal, Quebec, Canada
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16
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Kalman D, Whittaker K, Bishop JM, O'Lague PH. Domains of E1A that bind p105Rb, p130, and p300 are required to block nerve growth factor-induced neurite growth in PC12 cells. Mol Biol Cell 1993; 4:353-61. [PMID: 8507895 PMCID: PMC300937 DOI: 10.1091/mbc.4.4.353] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Nerve growth factor (NGF) causes PC12 cells to cease division and undergo sympathetic neuron-like differentiation, including neurite outgrowth. We have tested whether differentiation and division share overlapping control mechanisms in these cells. To do this, we have perturbed the activity of proteins known to participate in cell-cycle regulation by introducing the E1A oncogene or its mutant forms via microinjection into PC12 cells. The E1A protein binds to several putative cell cycle control proteins, including p105Rb (the product of the retinoblastoma susceptibility gene), as well as others of unknown function such as p130, p107, and p300. Similar to previous results, we find that wild-type E1A abrogates NGF-induced neurite extension. However, NGF does cause neurite outgrowth in the presence of E1A mutants known to have greatly reduced binding to either p105Rb and p130 or p300. Our experiments suggest that p105Rb, p130, and p300 may participate either in E1A-mediated inhibition of differentiation or in the NGF signal transduction pathway. We also report here that NGF affects phosphorylation of p105Rb, suggesting that Rb mediates at least some of NGF's effects. Our results raise the possibility that putative cell-cycle control proteins may participate not only in NGF-induced cessation of division but also in differentiation.
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Affiliation(s)
- D Kalman
- G.W. Hooper Foundation, University of California, San Francisco 94143
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17
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Blaut M, Whittaker K, Valdovinos A, Ackrell BA, Gunsalus RP, Cecchini G. Fumarate reductase mutants of Escherichia coli that lack covalently bound flavin. J Biol Chem 1989; 264:13599-604. [PMID: 2668268] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Menaquinol-fumarate oxidoreductase of Escherichia coli is a four-subunit membrane-bound complex that catalyzes the final step in anaerobic respiration when fumarate is the terminal electron acceptor. The catalytic domain of fumarate reductase consists of the FrdA subunit, which contains the active site, and a FAD prosthetic group covalently attached to His44, plus the FrdB subunit which contains at least two of the three nonidentical iron-sulfur clusters of the enzyme. To examine the role of covalently bound FAD in enzyme activity and electron transfer during anaerobic cell growth, site-directed mutagenesis was used to alter His44 of the FrdA subunit to a Ser, Cys, or Tyr residue. The resulting mutant enzyme complexes that were synthesized associated normally with the cytoplasmic membrane, but had decreased ability (greater than 70%) to reduce fumarate with reduced benzyl viologen, an artificial electron donor of low redox potential (Em = -359 mV; Clark, W. M. (1972) Oxidation-Reduction Potentials of Organic Systems, Robert E. Kreiger Publishing Co., Melbourne, FL). Even lower activities were measured when the higher potential, natural electron donor menaquinol was used, which, however, correlated with the slower growth rates of the different mutant complexes. In contrast to the normal enzyme, the mutant enzyme complexes were unable to oxidize succinate. Substitution of Arg for His44 produced a totally inactive enzyme complex that permitted no cell growth on nonfermentable substrates with fumarate as electron acceptor. All four mutant complexes contained noncovalently bound FAD in stoichiometric amounts. These data indicate a unique role of the 8 alpha-[N(3)-histidyl] FAD linkage in enzyme activity, by raising the redox potential of free FAD to permit reduction by both menaquinol and succinate.
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Affiliation(s)
- M Blaut
- Department of Microbiology, University of California, Los Angeles 90024
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18
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Blaut M, Whittaker K, Valdovinos A, Ackrell BA, Gunsalus RP, Cecchini G. Fumarate Reductase Mutants of Escherichia coli That Lack Covalently Bound Flavin. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)80039-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Johnson MK, Kowal AT, Morningstar JE, Oliver ME, Whittaker K, Gunsalus RP, Ackrell BA, Cecchini G. Subunit location of the iron-sulfur clusters in fumarate reductase from Escherichia coli. J Biol Chem 1988; 263:14732-8. [PMID: 2844784] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The subunit location of the [2Fe-2S], [3Fe-4S], and [4Fe-4S] clusters in Escherichia coli fumarate reductase has been investigated by EPR studies of whole cells or whole cells extracts of a fumarate reductase deletion mutant with plasmid amplified expression of discrete fumarate reductase subunits or groups of subunits. The results indicate that both the [2Fe-2S] and [3Fe-4S] clusters are located entirely in the iron-sulfur protein subunit. Information concerning the specific cysteine residues that ligate these clusters has been obtained by investigating the EPR characteristics of cells of the deletion mutant amplified with a plasmid coding for the flavoprotein subunit and a truncated iron-sulfur protein subunit. While the results are not definitive with respect to the location of the [4Fe-4S] cluster, they are most readily interpreted in terms of this cluster being entirely in the flavoprotein subunit or bridging between the two catalytic domain subunits. These new results are discussed in light of the amino acid sequences of the two subunits and the sequences of structurally well characterized iron-sulfur proteins containing [2Fe-2S], [3Fe-4S], and [4Fe-4S] centers.
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Affiliation(s)
- M K Johnson
- School of Chemical Sciences, University of Georgia, Athens 30602
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Johnson MK, Kowal AT, Morningstar JE, Oliver ME, Whittaker K, Gunsalus RP, Ackrell BA, Cecchini G. Subunit location of the iron-sulfur clusters in fumarate reductase from Escherichia coli. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)68098-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Davenport J, Whittaker K. Secondary prevention in elderly survivors of heart attacks. Am Fam Physician 1988; 38:216-24. [PMID: 2899386] [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: 01/03/2023]
Abstract
More than 200,000 elderly patients survive myocardial infarctions each year. Thus, the achievement of even minimal decreases in reinfarction and mortality rates will benefit large numbers of patients. Secondary prevention strategies include smoking cessation; the control of hyperlipidemia, obesity and diabetes; the management of hypertension and stress; exercise; the use of drugs such as beta blockers and aspirin, and increased attention to general health.
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Affiliation(s)
- J Davenport
- Kaiser Permanente Medical Center, Anaheim, California
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Abstract
A constitutional karyotypic abnormality, ins(16)(p11.2), is described in a case of myelodysplastic syndrome (MDS). The source of material for this insertion could not be established, but did not arise from either a balanced deletion or translocation, and did not consist of constitutive heterochromatin as defined by C-banding. The same lesion was found in both sisters, both nephews and four of the five great-nephews. Of these, all were phenotypically and haematologically normal, with the exception of a great-nephew who at the age at the age of 6 exhibits features compatible with partial trisomy 16p. The relationship of the karyotypic abnormality to the MDS and partial trisomy 16p in this family is discussed.
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Affiliation(s)
- R E Clark
- Department of Haematology, University of Wales College of Medicine, Cardiff, U.K
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Abstract
It has been suggested that a poor prognosis and the development of leukemia in patients with myelodysplasia may be related to chromosomal abnormalities. We measured the DNA content of bone marrow cells with flow cytometry in 19 hematologically normal subjects and in 70 patients who had recently been diagnosed as having myelodysplasia. Thirty-four of the patients were found to have aneuploidy. This was not related to the percentage of blast cells in the bone marrow, and there was no demarcation in terms of DNA content between patients with a high percentage of blast cells and those with a low percentage of such cells. Patients with hypodiploid marrow cells had a significantly shorter survival time than other patients (P = 0.001). Patients with hyperdiploid marrow and those whose marrow had a normal DNA content had similar survival times. Hypodiploidy appears to be a better indicator of poor survival than the marrow blast-cell count. Patients with sideroblastic anemia invariably had cells with a normal or high DNA content; none of these patients died during the study. Our data suggest that there is a relation between the loss of chromosomal material and progression toward a leukemic phenotype. It is tempting to speculate that this process may involve a loss of negative regulatory genes ("anti-oncogenes").
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Abstract
The effect of timolol vs placebo on the frequency of anginal episodes, nitroglycerin consumption and exercise performance was investigated in a double-blind, randomized, crossover study in 23 patients with angina pectoris. The optimal dose of timolol (10-30 mg twice daily) for each patient was titrated by exercise studies. Compared with placebo, timolol decreased the weekly number of anginal attacks and the weekly number of nitroglycerin tablets consumed, reduced the resting heart rate, systolic and diastolic blood pressure, and product of systolic blood pressure times heart rate, decreased the heart rate, systolic and diastolic blood pressure, and product of systolic blood pressure times heart rate at the onset of angina pectoris or marked fatigue, prolonged exercise duration, and diminished electrocardiographic evidence of myocardial ischemia. Timolol is an excellent antianginal agent when prescribed twice daily, with the optimal dose titrated by exercise studies.
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Abstract
The effect of the vasodilator prazosin vs placebo on exercise duration until marked dyspnea, and on left ventricular function measured by echocardiography, was evaluated in a double-blind, randomized study in 24 patients with chronic left ventricular failure despite digitalis and diuretic therapy. Compared with the double-blind placebo, prazosin reduced resting systolic and diastolic blood pressure and systolic blood pressure times heart rate, improved clinical symptoms, decreased cardiothoracic ratio measured by chest roentgenography, decreased left ventricular and left atrial dimensions, improved ejection fraction and Vcf measured by echocardiography, and improved treadmill exercise duration. All 12 patients taking prazosin had greater than or equal to 20% improved treadmill exercise duration; none of 12 receiving placebo improved. In six of 12 patients taking prazosin, roentgenographic evidence of pulmonary venous congestion disappeared compared with none of the patients on placebo. These data suggest that prazosin may be effective in treating chronic left ventricular failure.
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Abstract
The effect of intravenous acebutolol on supraventricular arrhythmias was evaluated in 20 patients, 5 with chronic obstructive pulmonary disease. A rapid ventricular rate in atrial fibrillation was slowed greater than 15% in all of 10 patients by acebutolol and in none of 5 patients by saline. A rapid ventricular rate in atrial flutter was slowed greater than 15% in all of 6 patients by acebutolol and in none of 3 patients by saline. Frequent premature atrial beats were abolished or reduced by greater than 75% in each of 2 patients by acebutolol and not in a patient by saline. Acebutolol converted multifocal atrial tachycardia to sinus rhythm in a patient. Digitalis-induced nonparoxysmal atrioventricular junctional tachycardia was not affected by saline but was abolished by acebutolol in a patient. Acebutolol was well tolerated in each of 5 patients with chronic obstructive pulmonary disease. Acebutolol is useful in the treatment of supraventricular arrhythmias.
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Abstract
The effect of intravenous acebutolol versus saline solution on frequent premature ventricular complexes was evaluated in a double-blind, randomized study in 20 patients, including 3 with chronic obstructive pulmonary disease. Frequent premature ventricular complexes were abolished or reduced by 75% or more in none of 12 patients given saline solution but in 18 of 20 patients (90%) given acebutolol (P less than 0.001). This therapeutic effect of acebutolol persisted for at least 2.5 hours in 17 of 20 patients (85%), for at least 3.5 hours in 14 (70%) and for at least 4 hours in 8 (40%). Acebutolol was well tolerated by the three patients with chronic obstructive pulmonary disease. These data indicate that intravenous acebutolol is useful in the treatment of premature ventricular complexes.
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