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Minassian C, Allen LA, Okosieme O, Vaidya B, Taylor P. Preconception Management of Hyperthyroidism and Thyroid Status in Subsequent Pregnancy: A Population-Based Cohort Study. J Clin Endocrinol Metab 2023; 108:2886-2897. [PMID: 37200150 PMCID: PMC10584009 DOI: 10.1210/clinem/dgad276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 01/18/2023] [Revised: 04/18/2023] [Accepted: 05/16/2023] [Indexed: 05/20/2023]
Abstract
CONTEXT Optimal thyroid status in pregnancy is essential in reducing the risk of adverse outcomes. The management of hyperthyroidism in women of reproductive age poses unique challenges and it is unclear how preconception treatment strategies impact on thyroid status in subsequent pregnancy. OBJECTIVE We aimed to determine trends in the management of hyperthyroidism before and during pregnancy and to assess the impact of different preconception treatment strategies on maternal thyroid status. METHODS We utilized the Clinical Practice Research Datalink database to evaluate all females aged 15-45 years with a clinical diagnosis of hyperthyroidism and a subsequent pregnancy (January 2000 to December 2017). We compared thyroid status in pregnancy according to preconception treatment, namely, (1) antithyroid drugs up to or beyond pregnancy onset, (2) definitive treatment with thyroidectomy or radioiodine before pregnancy, and (3) no treatment at pregnancy onset. RESULTS Our study cohort comprised 4712 pregnancies. Thyrotropin (TSH) was measured in only 53.1% of pregnancies, of which 28.1% showed suboptimal thyroid status (TSH >4.0 mU/L or TSH <0.1 mU/L plus FT4 >reference range). Pregnancies with prior definitive treatment were more likely to have suboptimal thyroid status compared with pregnancies starting during antithyroid drug treatment (odds ratio 4.72, 95% CI 3.50-6.36). A steady decline in the use of definitive treatment before pregnancy was observed from 2000 to 2017. One-third (32.6%) of first trimester carbimazole-exposed pregnancies were switched to propylthiouracil while 6.0% of propylthiouracil-exposed pregnancies switched to carbimazole. CONCLUSION The management of women with hyperthyroidism who become pregnant is suboptimal, particularly in those with preconception definitive treatment, and needs urgent improvement. Better thyroid monitoring and prenatal counseling are needed to optimize thyroid status, reduce teratogenic drug exposure, and ultimately reduce the risk of adverse pregnancy outcomes.
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Affiliation(s)
- Caroline Minassian
- Faculty of Epidemiology and Population Health, Department of Non-communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Lowri A Allen
- Diabetes Research Group, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Onyebuchi Okosieme
- Thyroid Research Group, Systems Immunity Research Institute Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Bijay Vaidya
- Department of Endocrinology, Royal Devon & Exeter Hospital, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Peter Taylor
- Thyroid Research Group, Systems Immunity Research Institute Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
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Allen LA, Taylor PN, Gillespie KM, Oram RA, Dayan CM. Maternal type 1 diabetes and relative protection against offspring transmission. Lancet Diabetes Endocrinol 2023; 11:755-767. [PMID: 37666263 DOI: 10.1016/s2213-8587(23)00190-0] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/12/2023] [Accepted: 06/16/2023] [Indexed: 09/06/2023]
Abstract
Type 1 diabetes is around twice as common in the offspring of men with type 1 diabetes than in the offspring of women with type 1 diabetes, but the reasons for this difference are unclear. This Review summarises the evidence on the rate of transmission of type 1 diabetes to the offspring of affected fathers compared with affected mothers. The findings of nine major studies are presented, describing the magnitude of the effect observed and the relative strengths and weaknesses of these studies. This Review also explores possible underlying mechanisms for this effect, such as genetic mechanisms (eg, the selective loss of fetuses with high-risk genes in mothers with type 1 diabetes, preferential transmission of susceptibility genes from fathers, and parent-of-origin effects influencing gene expression), environmental exposures (eg, exposure to maternal hyperglycaemia, exogenous insulin exposure, and transplacental antibody transfer), and maternal microchimerism. Understanding why type 1 diabetes is more common in the offspring of men versus women with type 1 diabetes will help in the identification of individuals at high risk of the disease and can pave the way in the development of interventions that mimic the protective elements of maternal type 1 diabetes to reduce the risk of disease in individuals at high risk.
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Affiliation(s)
- Lowri A Allen
- Diabetes Research Group, Cardiff University, University Hospital of Wales, Cardiff, UK.
| | - Peter N Taylor
- Diabetes Research Group, Cardiff University, University Hospital of Wales, Cardiff, UK
| | - Kathleen M Gillespie
- Diabetes and Metabolism, Bristol Medical School, University of Bristol, Southmead Hospital, Bristol, UK
| | - Richard A Oram
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Royal Devon and Exeter Hospital, Exeter, UK
| | - Colin M Dayan
- Diabetes Research Group, Cardiff University, University Hospital of Wales, Cardiff, UK
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Allen LA, Shrikrishnapalasuriyar N, Rees DA. Long-term health outcomes in young women with polycystic ovary syndrome: A narrative review. Clin Endocrinol (Oxf) 2022; 97:187-198. [PMID: 34617616 DOI: 10.1111/cen.14609] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 09/22/2021] [Accepted: 10/03/2021] [Indexed: 11/29/2022]
Abstract
Polycystic ovary syndrome (PCOS) has long been recognized as a common disorder in young women leading to reproductive and cutaneous sequelae. However, the associated health risks are now known to extend beyond these familiar manifestations to a range of longer-term comorbidities. Here we review the evidence for an association of PCOS with adverse long-term health outcomes, discussing the pathophysiological mechanisms involved in addition to opportunities for therapeutic intervention. Cross-sectional and longitudinal studies point to an increased risk of type 2 diabetes, hypertension and dyslipidaemia, with recent data confirming that these translate to an increased risk of cardiovascular events independently of obesity. Obstructive sleep apnoea, nonalcoholic fatty liver disease and endometrial cancer are also more prevalent, while mental health disorders, notably anxiety and depression, are common but under-appreciated associations. Uncertainties remain as to whether these risks are apparent in all patients with PCOS or are confined to particular subtypes, whether risks persist post-menopausally and how risk may be affected by ethnicity. Further work is also needed in establishing if systematic screening and targeted intervention can lead to improved outcomes. Until such data are available, clinicians managing women with PCOS should counsel patients on long-term health risks and invest in strategies that limit progression to metabolic and non-metabolic morbidities.
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Affiliation(s)
- Lowri A Allen
- Diabetes Research Group, School of Medicine, Cardiff University, Cardiff, UK
| | | | - Dafydd Aled Rees
- Neuroscience and Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, UK
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Abstract
INTRODUCTION Despite advances in technology including the development of more sophisticated methods of monitoring blood glucose and delivering insulin, many individuals with type 1 diabetes continue to experience significant challenges in optimizing glycaemic control. Alternative treatment approaches to insulin are required. Increasing efforts have focused on developing treatments aimed at targeting the underlying disease process to modulate the immune system, maximize beta cell function and enhance endogenous insulin production and action. SOURCES OF DATA Literature searches with keywords 'Type 1 diabetes and immunotherapy', publications relating to clinical trials of immunotherapy in type 1 diabetes. AREAS OF AGREEMENT Insulin therapy is insufficient to achieve optimal glycaemic control in many individuals with type 1 diabetes, and new treatment approaches are required. Studies have showed promising results for the use of immunotherapy as a means of delaying disease onset and progression. AREAS OF CONTROVERSY The optimal way of identifying individuals most likely to benefit from immunotherapies. GROWING POINTS A better understanding of the natural history of type 1 diabetes has made it possible to identify individuals who have developed autoimmunity but have not yet progressed to clinical diabetes, offering opportunities not only to develop treatments that delay disease progression, but prevent its development in the first place. A consensus on how to identify individuals who may benefit from immunotherapy to prevent disease onset is needed. AREAS TIMELY FOR DEVELOPING RESEARCH The development of optimal strategies for preventing and delaying progression of type 1 diabetes, and monitoring the response to immunointervention.
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Affiliation(s)
- L A Allen
- Diabetes Research Group, Cardiff University, Cardiff, UK
| | - C M Dayan
- Diabetes Research Group, Cardiff University, Cardiff, UK
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Allen LA, Cannings-John RL, Evans A, Thayer DS, French R, Paranjothy S, Fone DL, Dayan CM, Gregory JW. Pregnancy in teenagers diagnosed with type 1 diabetes mellitus in childhood: a national population-based e-cohort study. Diabetologia 2020; 63:799-810. [PMID: 31863141 PMCID: PMC7054376 DOI: 10.1007/s00125-019-05063-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/05/2019] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to describe the characteristics and outcomes of pregnancies in a national cohort of teenage (<20 years) and young adult women (≥20 years) with and without childhood-onset (<15 years) type 1 diabetes. We hypothesised that, owing to poor glycaemic control during the teenage years, pregnancy outcomes would be poorer in teenage mothers with type 1 diabetes than young adult mothers with type 1 diabetes and mothers without diabetes. METHODS The Brecon Register of childhood-onset type 1 diabetes diagnosed in Wales since 1995 was linked to population-based datasets in the Secure Anonymised Information Linkage (SAIL) Databank, creating an electronic cohort (e-cohort) of legal births (live or stillbirths beyond 24 weeks' gestation) to women aged less than 35 years between 1995 and 2013 in Wales. Teenage pregnancy rates were calculated based on the number of females in the same birth cohort in Wales. Pregnancy outcomes, including pre-eclampsia, preterm birth, low birthweight, macrosomia, congenital malformations, stillbirths and hospital admissions during the first year of life, were obtained from electronic records for the whole Welsh population. We used logistic and negative binomial regression to compare outcomes among teenage and young adult mothers with and without type 1 diabetes. RESULTS A total of 197,796 births were eligible for inclusion, including 330 to girls and women with childhood-onset type 1 diabetes, of whom 68 were teenagers (age 14-19 years, mean 17.9 years) and 262 were young adults (age 20-32 years, mean 24.0 years). The mean duration of diabetes was 14.3 years (9.7 years for teenagers; 15.5 years for young adults). Pregnancy rates were lower in teenagers with type 1 diabetes than in teenagers without diabetes (mean annual teenage pregnancy rate between 1999 and 2013: 8.6 vs 18.0 per 1000 teenage girls, respectively; p < 0.001). In the background population, teenage pregnancy was associated with deprivation (p < 0.001), but this was not the case for individuals with type 1 diabetes (p = 0.85). Glycaemic control was poor in teenage and young adult mothers with type 1 diabetes (mean HbA1c based on closest value to conception: 81.3 and 80.2 mmol/mol [9.6% and 9.5%], respectively, p = 0.78). Glycaemic control improved during pregnancy in both groups but to a greater degree in young adults, who had significantly better glycaemic control than teenagers by the third trimester (mean HbA1c: 54.0 vs 67.4 mmol/mol [7.1% vs 8.3%], p = 0.01). All adverse outcomes were more common among mothers with type 1 diabetes than mothers without diabetes. Among those with type 1 diabetes, hospital admissions during the first year of life were more common among babies of teenage vs young adult mothers (adjusted OR 5.91 [95% CI 2.63, 13.25]). Other outcomes were no worse among teenage mothers with type 1 diabetes than among young adult mothers with diabetes. CONCLUSIONS/INTERPRETATION Teenage girls with childhood-onset type 1 diabetes in Wales are less likely to have children than teenage girls without diabetes. Teenage pregnancy in girls with type 1 diabetes, unlike in the background population, is not associated with social deprivation. In our cohort, glycaemic control was poor in both teenage and young adult mothers with type 1 diabetes. Pregnancy outcomes were comparable between teenage and young adult mothers with type 1 diabetes, but hospital admissions during the first year of life were five times more common among babies of teenage mothers with type 1 diabetes than those of young adult mothers with diabetes.
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Affiliation(s)
- Lowri A Allen
- Diabetes Research Group , C2 link corridoe University Hospital of Wales Heath Park, Cardiff, CF14 4XN, UK.
| | | | - Annette Evans
- Division of Population Medicine, Cardiff University, Cardiff, UK
| | - Daniel S Thayer
- SAIL Databank, School of Medicine, Swansea University, Swansea, UK
| | - Robert French
- Diabetes Research Group , C2 link corridoe University Hospital of Wales Heath Park, Cardiff, CF14 4XN, UK
| | | | - David L Fone
- Division of Population Medicine, Cardiff University, Cardiff, UK
| | - Colin M Dayan
- Diabetes Research Group , C2 link corridoe University Hospital of Wales Heath Park, Cardiff, CF14 4XN, UK
| | - John W Gregory
- Division of Population Medicine, Cardiff University, Cardiff, UK
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Allen LA, Pyart RD, Holmes J, Donovan KL, Anderson RA, Phillips AO. Cardiovascular and renal outcomes following percutaneous coronary intervention in a population with renal disease: a case-control study. QJM 2019; 112:669-674. [PMID: 31161203 DOI: 10.1093/qjmed/hcz130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 05/01/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Patients with renal disease are less likely to undergo percutaneous coronary intervention (PCI) due to concerns about poor outcomes. AIM We describe outcomes following PCI in individuals with chronic kidney disease (CKD), as compared with matched controls with comparable CKD who did not undergo PCI. We also identified factors predictive of poor outcomes following PCI amongst patients with CKD. DESIGN Retrospective observational case-control study. METHODS Cases were individuals with CKD (stages 1-5) undergoing PCI between 2008 and 2014. Controls were age, gender and creatinine-matched individuals not requiring PCI. We compared mortality between groups using Kaplan-Meier curves and Cox regression modelling. We assessed changes in serum creatinine using Wilcoxon Rank testing. We explored the relationship between biochemical and haematological measures (baseline creatinine, calcium, phosphate, calcium-phosphate product, parathyroid hormone, white cell count, haemoglobin, platelet count, c-reactive protein and total cholesterol) and post-PCI mortality, using logistic regression. RESULTS We identified 144 cases and 144 controls. Mortality was significantly lower amongst cases compared with controls [hazard ratio 0.46 (95% confidence intervals 0.31, 0.69)]. PCI did not result in a significant change in renal function (P=0.52). Amongst cases, serum creatinine and calcium-phosphate product were predictors of mortality following PCI. CONCLUSION Cases undergoing PCI had lower mortality, and PCI was not associated with accelerated CKD progression. On this data, PCI should not be deferred as a treatment option in patients with CKD. Serum creatinine and calcium-phosphate product predict mortality following PCI in this cohort, and may be useful in risk-stratifying patients with CKD being considered for PCI.
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Affiliation(s)
- L A Allen
- Institute of Nephrology, Cardiff University School of Medicine, University Hospital of Wales, Heath Park, Cardiff, Wales, UK
| | - R D Pyart
- Institute of Nephrology, Cardiff University School of Medicine, University Hospital of Wales, Heath Park, Cardiff, Wales, UK
| | - J Holmes
- Institute of Nephrology, Cardiff University School of Medicine, University Hospital of Wales, Heath Park, Cardiff, Wales, UK
- Welsh Renal Clinical Network, Cwm Taf University Health Board, Wales, UK
| | - K L Donovan
- Institute of Nephrology, Cardiff University School of Medicine, University Hospital of Wales, Heath Park, Cardiff, Wales, UK
| | - R A Anderson
- Department of Cardiology, Cardiff University School of Medicine, University Hospital of Wales, Heath Park, Cardiff, Wales, UK
| | - A O Phillips
- Institute of Nephrology, Cardiff University School of Medicine, University Hospital of Wales, Heath Park, Cardiff, Wales, UK
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Phillips D, Young O, Holmes J, Allen LA, Roberts G, Geen J, Williams JD, Phillips AO. Seasonal pattern of incidence and outcome of Acute Kidney Injury: A national study of Welsh AKI electronic alerts. Int J Clin Pract 2017; 71. [PMID: 28869717 DOI: 10.1111/ijcp.13000] [Citation(s) in RCA: 14] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 08/08/2017] [Indexed: 12/01/2022] Open
Abstract
OBJECTIVES To identify any seasonal variation in the occurrence of, and outcome following Acute Kidney Injury. METHODS The study utilised the biochemistry based AKI electronic (e)-alert system established across the Welsh National Health Service to collect data on all AKI episodes to identify changes in incidence and outcome over one calendar year (1st October 2015 and the 30th September 2016). RESULTS There were total of 48 457 incident AKI alerts. The highest proportion of AKI episodes was seen in the quarter of January to March (26.2%), and the lowest in the quarter of October to December (23.3%, P < .001). The same trend was seen for both community-acquired and hospital-acquired AKI sub-sets. Overall 90 day mortality for all AKI was 27.3%. In contrast with the seasonal trend in AKI occurrence, 90 day mortality after the incident AKI alert was significantly higher in the quarters of January to March and October to December compared with the quarters of April to June and July to September (P < .001) consistent with excess winter mortality reported for likely underlying diseases which precipitate AKI. CONCLUSIONS In summary we report for the first time in a large national cohort, a seasonal variation in the incidence and outcomes of AKI. The results demonstrate distinct trends in the incidence and outcome of AKI.
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Affiliation(s)
- Dafydd Phillips
- Institute of Nephrology, Cardiff University School of Medicine, Cardiff, UK
| | - Oliver Young
- Institute of Nephrology, Cardiff University School of Medicine, Cardiff, UK
| | - Jennifer Holmes
- Welsh Renal Clinical Network, Cwm Taf University Health Board, Abercynon, UK
| | - Lowri A Allen
- Institute of Nephrology, Cardiff University School of Medicine, Cardiff, UK
| | - Gethin Roberts
- Department of Clinical Biochemistry, Hywel Dda University Health Board, Aberystwyth, UK
| | - John Geen
- Department of Clinical Biochemistry, Cwm Taf University Health Board, Merthyr, UK
- Faculty of Life Sciences and Education, University of South Wales, Cardiff, UK
| | - John D Williams
- Institute of Nephrology, Cardiff University School of Medicine, Cardiff, UK
| | - Aled O Phillips
- Institute of Nephrology, Cardiff University School of Medicine, Cardiff, UK
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Goodhead DT, Belli M, Mill AJ, Bance DA, Allen LA, Hall SC, Ianzani F, Simone G, Stevens DL, Stretch A. Direct Comparison between Protons and Alpha-particles of the Same LET: I. Irradiation Methods and Inactivation of Asynchronous V79, HeLa and C3H 10T½ Cells. Int J Radiat Biol 2009; 61:611-24. [PMID: 1349625 DOI: 10.1080/09553009214551421] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [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: 10/23/2022]
Abstract
A direct comparison was carried out of the biological effectiveness of protons and alpha-particles of the same linear energy transfer (LET) under identical conditions with a variety of in vitro biological systems. Monolayers of mammalian cells were irradiated with accelerated beams of protons (1.2 and 1.4 MeV) and alpha-particles (30 and 35 MeV) corresponding to LETs of 23 and 20 keV microns-1 for each particle type. For V79-4 cells it was observed that the linear term of the dose-response for cell inactivation by protons was significantly greater than that for alpha-particles of the same LET. For HeLa and HeLa S3 cells, also, the linear term appeared to be greater for protons, but this was not observed with more limited data for C3H 10T1/2 cells. The result for V79 cells is in agreement with the report of Belli et al. (1989) who observed that the biological effectiveness of protons rose sharply between 17 and 30 keV microns-1 in strong contrast to alpha-particles which reached a peak effectiveness at greater than 100 keV microns-1. These results place new constraints on the biologically relevant features of the microscopic structure of radiation tracks, and have implications for the mechanistic and practical comparison between radiations.
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Affiliation(s)
- D T Goodhead
- Medical Research Council, Radiobiology Unit, Didcot, Oxon, UK
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Kelly ME, Beavis RC, Fiorella D, Schültke E, Allen LA, Juurlink BH, Zhong Z, Chapman LD. Analyzer-based imaging of spinal fusion in an animal model. Phys Med Biol 2008; 53:2607-16. [PMID: 18441411 DOI: 10.1088/0031-9155/53/10/011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Analyzer-based imaging (ABI) utilizes synchrotron radiation sources to create collimated monochromatic x-rays. In addition to x-ray absorption, this technique uses refraction and scatter rejection to create images. ABI provides dramatically improved contrast over standard imaging techniques. Twenty-one adult male Wistar rats were divided into four experimental groups to undergo the following interventions: (1) non-injured control, (2) decortication alone, (3) decortication with iliac crest bone grafting and (4) decortication with iliac crest bone grafting and interspinous wiring. Surgical procedures were performed at the L5-6 level. Animals were killed at 2, 4 and 6 weeks after the intervention and the spine muscle blocks were excised. Specimens were assessed for the presence of fusion by (1) manual testing, (2) conventional absorption radiography and (3) ABI. ABI showed no evidence of bone fusion in groups 1 and 2 and showed solid or possibly solid fusion in subjects from groups 3 and 4 at 6 weeks. Metal artifacts were not present in any of the ABI images. Conventional absorption radiographs did not provide diagnostic quality imaging of either the graft material or fusion masses in any of the specimens in any of the groups. Synchrotron-based ABI represents a novel imaging technique which can be used to assess spinal fusion in a small animal model. ABI produces superior image quality when compared to conventional radiographs.
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Affiliation(s)
- M E Kelly
- Division of Neurosurgery, Royal University Hospital, University of Saskatchewan, Saskatoon, SK, Canada.
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Affiliation(s)
- L A Allen
- The Water Pollution Research Laboratory, Langley Road, Watford
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Affiliation(s)
- L A Allen
- The Department of Agricultural Bacteriology, University of Reading
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Abstract
Patients diagnosed with somatization disorder have high rates of disability and often prove refractory to treatment. This preliminary investigation examines the effect of a 10-session cognitive behavior therapy (CBT) protocol on the physical discomfort and disability of severely impaired somatizers. The severity of patients' physical discomfort and disability was assessed at baseline, post-treatment, and eight months following treatment. Patients reported significant improvement in symptomatology and physical functioning between baseline and post-treatment as well as between baseline and follow-up. The findings suggest that CBT might benefit patients diagnosed with somatization disorder and should be subjected to a controlled treatment trial.
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Affiliation(s)
- L A Allen
- Department of Psychiatry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854, USA.
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Abstract
Recent advances in our understanding of Helicobacter pylori-phagocyte interactions indicate that these organisms actively modulate phagocyte function in order to retard phagocytosis, while simultaneously inducing a strong respiratory burst. The central players in this dynamic include H. pylori neutrophil activating protein and factors that are associated with the cag pathogenicity island type IV secretion apparatus. Additionally, catalase, alkyl hydroperoxide reductase, and factors that are unique to type I strains allow bacteria to resist phagocytic killing.
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Affiliation(s)
- L A Allen
- Department of Medicine, Division of Infectious Diseases, and the Inflammation Program, University of Iowa and the Veterans Affairs Medical Center, Iowa City, Iowa 52242, USA.
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Gallois A, Klein JR, Allen LA, Jones BD, Nauseef WM. Salmonella pathogenicity island 2-encoded type III secretion system mediates exclusion of NADPH oxidase assembly from the phagosomal membrane. J Immunol 2001; 166:5741-8. [PMID: 11313417 DOI: 10.4049/jimmunol.166.9.5741] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Salmonella typhimurium requires a type III secretion system encoded by pathogenicity island (SPI)-2 to survive and proliferate within macrophages. This survival implies that S. typhimurium avoids or withstands bactericidal events targeted to the microbe-containing vacuole, which include intraphagosomal production of reactive oxygen species (ROS), phagosomal acidification, and delivery of hydrolytic enzymes to the phagosome via fusion with lysosomes. Recent evidence suggests that S. typhimurium alters ROS production by murine macrophages in an SPI-2-dependent manner. To gain insights into the mechanism by which S. typhimurium inhibits intraphagosomal ROS production, we analyzed the subcellular distribution of NADPH oxidase components during infection of human monocyte-derived macrophages by wild-type (WT) or several SPI-2 mutant strains of S. typhimurium. We found that the membrane component of the NADPH oxidase, flavocytochrome b(558), was actively excluded or rapidly removed from the phagosomal membrane of WT-infected monocyte-derived macrophages, thereby preventing assembly of the NADPH oxidase complex and intraphagosomal production of superoxide anion. In contrast, the NADPH oxidase assembled on and generated ROS in phagosomes containing SPI-2 mutant S. typhimurium. Subversion of NADPH oxidase assembly by S. typhimurium was accompanied by increased bacterial replication relative to that of SPI-2 mutant strains, suggesting that the ability of WT S. typhimurium to prevent NADPH oxidase assembly at the phagosomal membrane represents an important virulence factor influencing its intracellular survival.
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Affiliation(s)
- A Gallois
- The Inflammation Program and Department of Medicine, University of Iowa and the Veterans' Affairs Medical Center, Iowa City, IA 52242, USA
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Yang C, Mora S, Ryder JW, Coker KJ, Hansen P, Allen LA, Pessin JE. VAMP3 null mice display normal constitutive, insulin- and exercise-regulated vesicle trafficking. Mol Cell Biol 2001; 21:1573-80. [PMID: 11238894 PMCID: PMC86703 DOI: 10.1128/mcb.21.5.1573-1580.2001] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [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: 11/20/2022] Open
Abstract
To investigate the physiological function of the VAMP3 vesicle SNARE (v-SNARE) isoform in the regulation of GLUT4 vesicle trafficking, we generated homozygotic VAMP3 null mice by targeted gene disruption. The VAMP3 null mice had typical growth rate and weight gain, with normal maintenance of fasting serum glucose and insulin levels. Analysis of glucose disposal and insulin sensitivity demonstrated normal insulin and glucose tolerance, with no evidence for insulin resistance. Insulin stimulation of glucose uptake in isolated primary adipocytes was essentially the same for the wild-type and VAMP3 null mice. Similarly, insulin-, hypoxia-, and exercise-stimulated glucose uptake in isolated skeletal muscle did not differ significantly. In addition, other general membrane trafficking events including phagocytosis, pinocytosis, and transferrin receptor recycling were also found to be unaffected in the VAMP3 null mice. Taken together, these data demonstrate that VAMP3 function is not necessary for either regulated GLUT4 translocation or general constitutive membrane recycling.
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Affiliation(s)
- C Yang
- Department of Physiology and Biophysics, The University of Iowa, Iowa City, Iowa 52242, USA
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Abstract
Somatization is a significant problem for clinical medicine. Unlike somatization disorder, which is relatively rare, abridged somatization, a less severe form of somatization, is prevalent in primary care clinics. The authors examined the clinical status and functioning of patients diagnosed with a depression or anxiety disorder comorbid with abridged somatization and compared them with patients diagnosed with a depression or anxiety disorder alone. The authors examined severity of physical functioning and psychopathology in relation to diagnostic status. Patients diagnosed with both abridged somatization and a depression or anxiety disorder were more physically impaired and more anxious than those diagnosed with a depression or anxiety disorder alone. The results suggest that abridged somatization frequently coexists with depression and anxiety and thus complicates the presentation of these disorders.
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Affiliation(s)
- L A Allen
- Department of Psychiatry, University of Medicine and Dentisitry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854, USA
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Yang HT, Feng Y, Allen LA, Protter A, Terjung RL. Efficacy and specificity of bFGF increased collateral flow in experimental peripheral arterial insufficiency. Am J Physiol Heart Circ Physiol 2000; 278:H1966-73. [PMID: 10843895 DOI: 10.1152/ajpheart.2000.278.6.h1966] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiogenic growth factors could prove to be useful in managing peripheral arterial insufficiency. The present study was designed to evaluate the dose response of basic fibroblast growth factor (bFGF), the efficacy of critical routes and dosing regimens, and the specificity of action in rats with peripheral arterial insufficiency. Bilateral ligation of femoral arteries greatly reduces blood flow capacity to the calf muscles but does not impair resting flow needs. Collateral blood flow to calf muscles was determined 16 days postocclusion, during treadmill running, with (85)Sr and (141)Ce microspheres, in blinded-randomized trials that included intra-arterial and intravenous infusions and subcutaneous injections of recombinant human bFGF. Peak blood flow of 75-80 ml. min(-1). 100 g(-1) for calf muscle was observed at a bFGF dose of 5 microg. kg(-1). day(-1) (ia for 14 days) compared with 50 ml. min(-1). 100 g(-1) for vehicle groups. Similar increases in collateral blood flow were observed with short-term or prolonged and continuous or intermittent delivery of bFGF by any route. Collateral blood flows were similar in corresponding muscles across both limbs. Vascular remodeling induced by bFGF required attendant vascular occlusion, inasmuch as vessels in the normal nonoccluded vascular tree were unresponsive to circulating bFGF. Improvement in collateral blood flow with exogenous bFGF is robust, amenable to short-term administration, and requires vascular occlusion to be effective.
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Affiliation(s)
- H T Yang
- Department of Physiology, State University of New York Health Science Center, Syracuse, NY 13210, USA
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18
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Affiliation(s)
- L A Allen
- Department of Medicine and the Inflammation Program, University of Iowa and the Veteran's Affairs Medical Center, Iowa City, Iowa 52242, USA.
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Gara MA, Allen LA, Herzog EP, Woolfolk RL. The abused child as parent: the structure and content of physically abused mothers' perceptions of their babies. Child Abuse Negl 2000; 24:627-639. [PMID: 10819095 DOI: 10.1016/s0145-2134(00)00130-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
OBJECTIVE The major aim of the study was to provide an empirical answer to the following question: Does a mother's history of being physically abused as a child have a discernible impact on the structure and content of her perceptions and beliefs concerning her own child? METHOD Free-response memories and current descriptions of babies, self, and significant others such as parents were compared longitudinally in two groups of mothers when their babies were 6 months, 1 year, and 2 years old. One group of mothers consisted of individuals who reported being physically abused as children; the control group consisted of mothers who were not physically abused. The two groups were comparable with respect to age of baby, race, and socioeconomic status. RESULTS Abused mothers were found to differ significantly from control mothers in the structure and content of their free-response perceptions of their own babies. More specifically, abused mothers lagged behind controls in how well-differentiated were their negative perceptions of their babies. Differentiation in this study is operationally defined as the number of unique clusters that underlie a mother's perceptions of her baby, when social perception data is analyzed using cluster analysis (HICLAS). The greater the number of clusters observed, the greater is the differentiation. On the other hand, abused mothers were comparable to controls with respect to differentiation of positive perceptions of babies. CONCLUSIONS The findings constitute a discovery about the structural organization of social cognition in mothers at-risk for child abuse. Implications of the findings for theory and future research are briefly discussed, as are limitations of the current study.
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Affiliation(s)
- M A Gara
- UMDNJ-Robert Wood Johnson Medical School, Department of Psychiatry, Piscataway, NJ 08855-1392, USA
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20
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Abstract
Helicobacter pylori colonizes the gastric epithelium of approximately 50% of the world's population and plays a causative role in the development of gastric and duodenal ulcers. H. pylori is phagocytosed by mononuclear phagocytes, but the internalized bacteria are not killed and the reasons for this host defense defect are unclear. We now show using immunofluorescence and electron microscopy that H. pylori employs an unusual mechanism to avoid phagocytic killing: delayed entry followed by homotypic phagosome fusion. Unopsonized type I H. pylori bound readily to macrophages and were internalized into actin-rich phagosomes after a lag of approximately 4 min. Although early (10 min) phagosomes contained single bacilli, H. pylori phagosomes coalesced over the next approximately 2 h. The resulting "megasomes" contained multiple viable organisms and were stable for 24 h. Phagosome-phagosome fusion required bacterial protein synthesis and intact host microtubules, and both chloramphenicol and nocodazole increased killing of intracellular H. pylori. Type II strains of H. pylori are less virulent and lack the cag pathogenicity island. In contrast to type I strains, type II H. pylori were rapidly ingested and killed by macrophages and did not stimulate megasome formation. Collectively, our data suggest that megasome formation is an important feature of H. pylori pathogenesis.
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Affiliation(s)
- L A Allen
- Department of Medicine, University of Iowa, Veterans Affairs Medical Center, Iowa City, Iowa 52242, USA.
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Abstract
Laura Bragg, a member of the first graduating class at Simmons College, journeyed to Charleston as a New Woman in 1909. As the first woman director of a major scientific museum in the United States, Bragg transformed the Charleston Museum into a public education institution and became an innovative leader in museum education. This article documents Bragg's contributions within the context of antebellum culture where the Southern Belle was placed on a Victorian pedestal and Boston marriages were an unknown phenomenon. Using extensive and hitherto unpublished correspondence, the authors detail Bragg's lesbian relationships and describe her network within the homosexual male community during the era of the Charleston Renaissance.
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DeLeo FR, Allen LA, Apicella M, Nauseef WM. NADPH oxidase activation and assembly during phagocytosis. J Immunol 1999; 163:6732-40. [PMID: 10586071] [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] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Generation of superoxide (O2-) by the NADPH-dependent oxidase of polymorphonuclear leukocytes is an essential component of the innate immune response to invading microorganisms. To examine NADPH oxidase function during phagocytosis, we evaluated its activation and assembly following ingestion of serum-opsonized Neisseria meningitidis, serogroup B (NMB), and compared it with that elicited by serum-opsonized zymosan (OPZ). Opsonized N. meningitidis- and OPZ-dependent generation of reactive oxygen species by polymorphonuclear leukocytes peaked early and then terminated. Phosphorylation of p47phox coincided with peak generation of reactive oxygen species by either stimulus, consistent with a role for p47phox phosphorylation during NADPH oxidase activation, and correlated with phagosomal colocalization of flavocytochrome b558 (flavocytochrome b) and p47phox and p67phox (p47/67phox). Termination of respiratory burst activity did not reflect dephosphorylation of plasma membrane- and/or phagosome-associated p47phox; in contrast, the specific activity of phosphorylated p47phox at the phagosomal membrane increased. Most significantly, termination of oxidase activity paralleled the loss of p47/67phox from both NMB and OPZ phagosomes despite the continued presence of flavocytochrome b. These data suggest that 1) the onset of respiratory burst activity during phagocytosis is linked to the phosphorylation of p47phox and its translocation to the phagosome; and 2) termination of oxidase activity correlates with loss of p47/67phox from flavocytochrome b-enriched phagosomes and additional phosphorylation of membrane-associated p47phox.
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Affiliation(s)
- F R DeLeo
- Inflammation Program, Department of Medicine, Veterans Administration Medical Center, University of Iowa, Iowa City 52246, USA
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23
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Abstract
Helicobacter pylori colonizes the gastric epithelium of humans and plays a causative role in peptic ulcer disease and perhaps gastric cancer. H. pylori proliferates in the mucus layer over the epithelium and is not cleared by the host immune response. Although the mucus layer is the major reservoir of H. pylori in vivo, a growing body of evidence suggests that H. pylori can persist in multiple intracellular locales. Clinical isolates of H. pylori invade epithelial monolayers at least as well as Shigella. The intracellular organisms are cytotoxic, and bacterial microcolonies form on the exposed basement membrane. Both mononuclear phagocytes and neutrophils phagocytose unopsonized H. pylori. However, the internalized organisms are not killed efficiently and our recent data suggest that H. pylori disrupts phagosome maturation. Collectively, the data support the hypothesis that intracellular H. pylori represent a reservoir of organisms that contributes to bacterial persistence, host tissue damage, and treatment failure.
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Affiliation(s)
- L A Allen
- Department of Medicine, University of Iowa and the Veterans Administration Medical Center, Iowa City 52242, USA.
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24
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Abstract
Self-complexity, a measure of the structure of cognition involving the self, was used to predict the persistence of depression in patients diagnosed with major depression. Self-descriptions offered by depressed patients were analyzed using a clustering algorithm to model cognitive structure. Indices of positive and negative self-complexity, derived from the resulting models, were used to predict depressive symptomatology 9 months after the onset of a major depression. Negative self-complexity uniquely predicted subsequent levels of depression even after the effects of initial levels of depression, self-evaluation, and dysfunctional attitudes were statistically removed. Highly complex negative self-representation appears to be associated with poor recovery from a major depressive episode. Future studies examining the relationship between cognition and psychopathology should investigate, in addition to its content, the formal and structural properties of cognition.
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Affiliation(s)
- R L Woolfolk
- Department of Psychology, Rutgers University, Piscataway, New Jersey 08854-8040, USA
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25
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Allen LA, DeLeo FR, Gallois A, Toyoshima S, Suzuki K, Nauseef WM. Transient association of the nicotinamide adenine dinucleotide phosphate oxidase subunits p47phox and p67phox with phagosomes in neutrophils from patients with X-linked chronic granulomatous disease. Blood 1999; 93:3521-30. [PMID: 10233905] [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: 02/12/2023] Open
Abstract
Optimal microbicidal activity of polymorphonuclear leukocytes (PMNs) requires recruitment of a functional nicotinamide adenine dinucleotide phosphate (NADPH) oxidase to the phagosome. In this study, we used a synchronized phagocytosis assay and immunofluorescence microscopy (IFM) to examine the association of cytosolic NADPH oxidase subunits with phagosomes containing opsonized zymosan (OpZ). Ingestion of OpZ began within 30 seconds of particle binding and forming phagosomes were enriched for both F-actin and the actin-binding protein p57. NADPH oxidase subunits p47phox and p67phox were also recruited to forming phagosomes and were retained on mature phagosomes for at least 15 minutes. Colocalization of F-actin, p57, and p47phox on phagosomes was confirmed by immunoblotting. Translocation of p67phox, but not p57, to forming phagosomes was deficient in PMNs lacking p47phox. Surprisingly, we found that in PMNs from six individuals with X-linked chronic granulomatous disease (CGD), p47phox and p67phox accumulated in the periphagosomal area during ingestion of OpZ. However, in marked contrast to normal PMNs, p47phox and p67phox were shed from nascent phagosomes along with F-actin and p57 once OpZ was internalized (approximately 5 minutes). These data support a model in which flavocytochrome b is required for stable membrane binding of p47phox and p67phox, but not their association with the cytoskeleton or transport to the cell periphery.
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Affiliation(s)
- L A Allen
- The Inflammation Program and Department of Medicine, Division of Infectious Diseases, University of Iowa and the Veterans Affairs Medical Center, Iowa City, IA, USA
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26
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Allen LA. Treating agitation without drugs. Am J Nurs 1999; 99:36-41; quiz 42. [PMID: 10234322] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- L A Allen
- Division of Community Internal Medicine and Geriatrics, Mayo Medical Center, Rochester, MN, USA
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27
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Abstract
The Food and Drug Administration approved the use of buspirone for generalized anxiety disorder (GAD) in 1986. Since then, numerous studies have examined the efficacy and safety of buspirone for patients with not only generalized feelings of anxiety, but also panic disorder, major depressive disorder, obsessive-compulsive disorder, body dysmorphic disorder, social phobia, posttraumatic stress disorder, selective serotonin reuptake inhibitor-induced adverse events, dementia, behavioral disturbances, attention deficit-hyperactivity disorder, and tobacco dependency. Although relatively few placebo-controlled trials have been conducted on patients with problems other than GAD, an ever-growing body of research suggests future directions for the use of buspirone. This article reviews the body of research relating to new uses for buspirone.
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Affiliation(s)
- J T Apter
- Princeton Biomedical Research, PA, New Jersey, USA
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28
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Lehane MM, Bryant PE, Riches AC, Allen LA, Briscoe CV, Melville J, Mill AJ. 238Pu alpha-particle-induced C3H10T1/2 transformants are less tumorigenic than the X-ray-induced equivalent. Carcinogenesis 1999; 20:35-40. [PMID: 9934847 DOI: 10.1093/carcin/20.1.35] [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: 11/12/2022] Open
Abstract
Transformation is a complex multistage process in vitro by which benign cells gradually acquire characteristics of tumour cells. Transformed C3H10T1/2 cells appear in vitro as multilayers of cells termed foci. A variety of transformed phenotypes are observed in vitro and in this study samples of these phenotypes were developed as cell lines and assessed for their ability to induce tumours in C3H mice. It was found that, while a high proportion of X-ray-induced transformants were tumorigenic, most of the alpha-particle-induced transformants were non-tumorigenic. Although tumours produced by the X-ray-induced transformants appeared earlier, they grew at similar rates to the alpha-particle-induced equivalent. Foci were classified as fully or partially tumorigenic depending on whether the foci produced at least one tumour in the mice injected (partially tumorigenic) or produced tumours in all mice injected (fully tumorigenic). It was found that tumours from the partially tumorigenic foci grew slower or appeared later than those of the fully tumorigenic foci. It is hypothesized that the apparent low tumorigenicity of positively transformed alpha-particle-induced foci is due to an increase in genomic instability of progeny focus cells compared with X-ray-induced foci leading to a larger non-viable population of cells in the alpha-particle-induced foci.
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Affiliation(s)
- M M Lehane
- Radiobiology Laboratory, Nuclear Electric Ltd, Berkeley Centre, UK.
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29
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Allen LA, Wingertzahn MA, Teichberg S, Wapnir RA. Proabsorptive effect of glycerol as a glucose substitute in oral rehydration solutions. J Nutr Biochem 1999; 10:49-55. [PMID: 15539250 DOI: 10.1016/s0955-2863(98)00082-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/1988] [Accepted: 09/10/1998] [Indexed: 11/15/2022]
Abstract
We hypothesized that glycerol, a readily diffusable hydrophilic substance, may effectively substitute for glucose and enhance intestinal water and sodium absorption in an oral rehydration solution (ORS). This was evaluated using a low osmolality (230-240 mOsm/kg) ORS containing 75 mmol/L sodium and a combination of glucose:glycerol (in mmol/L) 75:0, 50:25; 37.5:37.5, 25:50, 10:65, or 0:75 during 3-hour long in vivo rat jejunal perfusions. Water, sodium, potassium, glucose and glycerol absorption, and unidirectional fluid movement (J(in), J(eff)) were determined. Sodium and net water absorptions were maximal at glucose:glycerol ratios between 37.5:37.5 and 10:65 mmol/L. In the absence of glucose (0:75), absorption of water and electrolytes was lower than at any other concentration. The greater net rehydration seemed to be due to a higher J(in) as glycerol was increased up to 65 mmol/L. Potassium absorption followed a similar pattern. With 50 mmol/L glycerol and 25 mmol/L glucose, there was a marked expansion of the lamina propria extracellular space and increased intercellular expansion between enterocytes. These results indicate that glycerol may be an effective partial substitute for glucose in ready-to-use ORS by producing an improved rate of water and electrolyte absorption.
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Affiliation(s)
- L A Allen
- Department of Pediatrics, North Shore University Hospital, New York University School of Medicine, Manhasset, NY 11030, USA
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30
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Abstract
MacMARCKS (also known as myristoylated alanine-rich protein kinase C substrate (MARCKS)-related protein) is a member of the MARCKS family of protein kinase C substrates. MacMARCKS contains within it a basic effector domain that contains the serine residues that are phosphorylated by protein kinase C, as well as a calcium/calmodulin and actin-binding site. Two previous reports demonstrated that a macrophage cell line expressing a mutant form of MacMARCKS that lacks the effector domain is defective in phagocytosis and cell adhesion (Zhu, Z., Bao, Z., and Li, J. (1995) J. Biol. Chem. 270, 17652-17655; Li, J., Zhu, Z., and Bao, Z. (1996) J. Biol. Chem. 271, 12985-12990). We report here that macrophages from MacMARCKS null mice phagocytose and spread normally. Thus, although MacMARCKS is recruited to phagosomes, it is not absolutely required for phagocytosis.
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Affiliation(s)
- D M Underhill
- Department of Immunology, University of Washington, H-574 Health Sciences, Seattle, Washington 98195, USA
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31
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Mill AJ, Frankenberg D, Bettega D, Hieber L, Saran A, Allen LA, Calzolari P, Frankenberg-Schwager M, Lehane MM, Morgan GR, Pariset L, Pazzaglia S, Roberts CJ, Tallone L. Transformation of C3H 10T1/2 cells by low doses of ionising radiation: a collaborative study by six European laboratories strongly supporting a linear dose-response relationship. J Radiol Prot 1998; 18:79-100. [PMID: 9656189 DOI: 10.1088/0952-4746/18/2/004] [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: 05/22/2023]
Abstract
For the assessment of radiation risk at low doses, it is presumed that the shape of the low-dose-response curve in humans for cancer induction is linear. Epidemiological data alone are unlikely to ever have the statistical power needed to confirm this assumption. Another approach is to use oncogenic transformation in vitro as a surrogate for carcinogenesis in vivo. In mid-1990, six European laboratories initiated such an approach using C3H 10T1/2 mouse cells. Rigid standardisation procedures were established followed by collaborative measurements of transformation down to absorbed doses of 0.25 Gy of x-radiation resulting in a total of 759 transformed foci. The results clearly support a linear dose-response relationship for cell transformation in vitro with no evidence for a threshold dose or for an enhanced, supralinear response at doses approximately 200-300 mGy. For radiological protection this represents a large dose, and the limitations of this approach are apparent. Only by understanding the fundamental mechanisms involved in radiation carcinogenesis will further knowledge concerning the effects of low doses become available. These results will, however, help validate new biologically based models of radiation cancer risk thus providing increased confidence in the estimation of cancer risk at low doses.
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Affiliation(s)
- A J Mill
- Faculty of Applied Sciences, University of the West of England, Bristol, UK.
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32
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Abstract
The dynamic rearrangement of the actin cytoskeleton is fundamental to most biological processes including embryogenesis, morphogenesis, cell movement, wound healing and metastasis [1]. Membrane ruffling and reversible cell-substratum interactions underlie actin-driven cell movement. Protein kinase C (PKC) stimulates membrane ruffling and adhesion [2], but the mechanism by which this occurs is unknown. Myristoylated alaninerich C kinase substrate (MARCKS) is a PKC substrate that cycles on and off membranes by a mechanism termed the myristoyl-electrostatic switch [3-6]. While at the membrane, MARCKS binds to and sequesters acidic phospholipids including phosphatidyl-inositol-4,5-bisphosphate (PIP2) [7]. MARCKS also binds and cross-links filamentous actin, an activity which is regulated by PKC-dependent phosphorylation and calcium-calmodulin [3]. In this report, we demonstrate that expression, in fibroblasts, of MARCKS containing a mutation which abrogates the myristoyl-electrostatic switch prevents cell spreading. The MARCKS mutant arrests the cell during an early stage of spreading, characterized by profuse membrane blebbing, and prevents the formation of membrane ruffles and lamellae usually found at the leading edge of spreading cells. This defect in the regulation of the actin cytoskeleton is accompanied by a decrease in cell-substratum adhesion. Our results provide direct evidence that MARCKS and PKC regulate actin-dependent membrane ruffling and cell adhesion, perhaps via a PIP2-dependent mechanism.
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Affiliation(s)
- M M Myat
- University of Washington, Department of Immunology, Seattle 98195-7650, USA
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Burke PV, Raitt DC, Allen LA, Kellogg EA, Poyton RO. Effects of oxygen concentration on the expression of cytochrome c and cytochrome c oxidase genes in yeast. J Biol Chem 1997; 272:14705-12. [PMID: 9169434 DOI: 10.1074/jbc.272.23.14705] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.4] [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: 02/04/2023] Open
Abstract
Oxygen is an important environmental regulator for the transcription of several genes in Saccharomyces cerevisiae, but it is not yet clear how this yeast or other eukaryotes actually sense oxygen. To begin to address this we have examined the effects of oxygen concentration on the expression of several nuclear genes (CYC1, CYC7, COX4, COX5a, COX5b, COX6, COX7, COX8, and COX9) for proteins of the terminal portion of the respiratory chain. COX5b and CYC7 are hypoxic genes; the rest are aerobic genes. We have found that the level of expression of these genes is determined by oxygen concentration per se and not merely the presence or absence of oxygen and that each of these genes has a low oxygen threshold (0. 5-1 microM O2) for expression. For some aerobic genes (COX4, COX5a, COX7, COX8, and COX9) there is a gradual decline in expression between 200 microM O2 (air) and their oxygen threshold. Below this threshold expression drops precipitously. For others (COX5a and CYC1) the level of expression is nearly constant between 200 microM O2 and their threshold and then drops off. The hypoxic genes COX5b and CYC7 are not expressed until the oxygen concentration is below 0.5 microM O2. These studies have also revealed that COX5a and CYC1, the genes for the aerobic isoforms of cytochrome c oxidase subunit V and cytochrome c, and COX5b and CYC7, the genes for the hypoxic isoforms of cytochrome c oxidase subunit V and cytochrome c, are coexpressed at a variety of oxygen concentrations and switch on or off at extremely low oxygen concentrations. By shifting cells from one oxygen concentration to another we have found that aerobic genes are induced faster than hypoxic genes and that transcripts from both types of gene are turned over quickly. These findings have important implications for cytochrome c oxidase function and biogenesis and for models of oxygen sensing in yeast.
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Affiliation(s)
- P V Burke
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
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Abstract
Ratings of possible selves and resultant self-concept discrepancies were examined in 25 patients diagnosed with major depression and 25 control subjects. Self-concept discrepancies significantly discriminated patients from controls. The presence of negative features in the self-schema was a stronger indicator of depressive symptomatology than was the absence of positive self-appraisal. Depressives' future projections of self were less pessimistic than predicted by cognitive theories of depression.
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Affiliation(s)
- L A Allen
- Princeton Biomedical Research, New Jersey, USA
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35
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Abstract
MARCKS is a protein kinase C (PKC) substrate which binds calcium/calmodulin and actin, and which has been implicated in cell motility, phagocytosis, membrane traffic, and mitogenesis. MARCKS cycles on and off the membrane via a myristoyl electrostatic switch (McLaughlin, S., and Aderem, A.(1995) Trends Biochem. Sci. 20, 272-276). Here we define the molecular determinants of the myristoyl-electrostatic switch. Mutation of the N-terminal glycine results in a nonmyristoylated form of MARCKS which does not bind membranes and is poorly phosphorylated. This indicates that myristic acid targets MARCKS to the membrane, where it is efficiently phosphorylated by PKC. A chimeric protein in which the N terminus of MARCKS is replaced by a sequence, which is doubly palmitoylated, is phosphorylated by PKC but not released from the membrane. Thus two palmitic acid moieties confer sufficient membrane binding energy to render the second, electrostatic membrane binding site superfluous. Mutation of the PKC phosphorylation sites results in a mutant which does not translocate from the membrane to the cytosol. A mutant in which the intervening sequence between the myristoyl moiety and the basic effector domain is deleted, is not displaced from the membrane by PKC dependent phosphorylation, fulfilling a theoretical prediction of the model. In addition to the nonspecific membrane binding interactions conferred by the myristoyl-electrostatic switch, indirect immunofluorescence microscopy demonstrates that specific protein-protein interactions also specify the intracellular localization of MARCKS.
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Affiliation(s)
- J T Seykora
- Laboratory of Signal Transduction, The Rockefeller University, New York, New York 10021, USA
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Allen LA, Aderem A. Molecular definition of distinct cytoskeletal structures involved in complement- and Fc receptor-mediated phagocytosis in macrophages. J Exp Med 1996; 184:627-37. [PMID: 8760816 PMCID: PMC2192718 DOI: 10.1084/jem.184.2.627] [Citation(s) in RCA: 325] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
It has long been known from the results of ultrastructural studies that complement- and immunoglobulin G (IgG)-opsonized particles are phagocytosed differently by macrophages (Kaplan. G. 1977. Scand. J. Immunol. 6:797-807). Complement-opsonized particles sink into the cell, whereas IgG-coated particles are engulfed by lamellipodia, which project from the cell surface. The molecular basis for these differences is unknown. We used indirect immunofluorescence and confocal microscopy to examine how cytoskeletal proteins associate with phagosomes containing complement-opsonized zymosan (COZ) particles or IgG beads in phorbol-myristateacetate-treated peritoneal macrophages. During ingestion of COZ, punctate structures rich in F-actin, vinculin, alpha-actinin, paxillin, and phosphotyrosine-containing proteins are distributed over the phagosome surface. These foci are detected beneath bound COZ within 30 s of warming the cells to 37 degrees C, and their formation requires active protein kinase C. By contrast, during Fc receptor-mediated phagocytosis, all proteins examined were uniformly distributed on or near the phagosome surface. Moreover, ingestion of IgG beads was blocked by tyrosine kinase inhibitors, whereas phagocytosis of COZ was not. Thus, the signals required for particle ingestion, and the arrangement of cytoskeletal proteins on the phagosome surface, vary depending upon which phagocytic receptor is engaged. Moreover, complement receptor (CR)-mediated internalization required intact microtubules and was accompanied by the accumulation of vesicles beneath the forming phagosome, suggesting that membrane trafficking plays a key role in CR-mediated phagocytosis.
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Affiliation(s)
- L A Allen
- Laboratory of Signal Transduction, Rockefeller University, New York, NY 10021, USA
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Abstract
Recent advances in research on phagocytosis include a better appreciation of the cross-talk between phagocytic receptors, the definition of multiple signaling domains within these receptors, and a deeper understanding of the downstream effector pathways leading to actin polymerization and particle internalization. Phagosome maturation in macrophages proceeds via a series of membrane fusion and fission events, which modify the phagosome in small increments, and appears to be regulated, in part, by GTP-binding proteins and perhaps by protein kinase C. The isolation of dysphagic mutants of Dictyostelium discoideum presages the identification of new genes required for phagocytosis.
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Affiliation(s)
- L A Allen
- Laboratory of Signal Transduction, Rockefeller University, New York, NY 10021, USA.
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Woolfolk RL, Novalany J, Gara MA, Allen LA, Polino M. Self-complexity, self-evaluation, and depression: an examination of form and content within the self-schema. J Pers Soc Psychol 1995. [PMID: 7608857 DOI: 10.1037//0022-3514.68.6.1108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Six studies examined the relationship between self-complexity and variables related to self-evaluation. Self-complexity was found to comprise two components: positive self-complexity and negative self-complexity. Positive self-complexity was sensitive to methodological factors, namely, variations in stimulus materials used for self-ratings. Negative self-complexity was relatively stable in the face of different rating stimuli and tasks and was related to trait measures of self-evaluation, psychic distress, and psychopathology. These findings were observed and replicated. Higher negative self-complexity was associated with increases in depression symptoms over time. Higher negative self-complexity also predicted a poorer prognosis and less complete recovery from depression in a clinical sample. Results are discussed in light of related research and possible social-cognitive mechanisms.
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Affiliation(s)
- R L Woolfolk
- Department of Psychology, Rutgers-State University of New Jersey, New Brunswick 08903, USA
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Abstract
Two groups of drug users on an inner-city inpatient drug detoxification unit were studied: 42 heroin addicts and 47 cocaine addicts. The two groups were compared on personality disorder diagnoses, personality traits, and demographic variables. Cocaine and heroin addicts scored similarly on: 1) number and kind of personality disorder diagnoses, with the exception of antisocial personality; 2) all personality traits measured; 3) positive and negative temperament; 4) description of self-concepts; and 5) positivity and negativity of self-concepts. It was also found that heroin addicts showed significantly higher levels of social deviance than the cocaine group, with significantly more antisocial personality disorder diagnoses, higher levels of social deviance, and lower scores on a Propriety Scale. Character pathology was more heterogeneous among cocaine users. Heroin addicts had used significantly longer and showed less educational and occupational achievement than the cocaine group. Our results also suggest that personality psychopathology in drug addicts is associated with lower self-esteem, more negative self-valuation, and longer duration of use.
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Affiliation(s)
- N P Fieldman
- Interfaith Medical Center, Brooklyn, New York 11238, USA
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Woolfolk RL, Novalany J, Gara MA, Allen LA, Polino M. Self-complexity, self-evaluation, and depression: an examination of form and content within the self-schema. J Pers Soc Psychol 1995; 68:1108-20. [PMID: 7608857 DOI: 10.1037/0022-3514.68.6.1108] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.1] [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: 01/26/2023]
Abstract
Six studies examined the relationship between self-complexity and variables related to self-evaluation. Self-complexity was found to comprise two components: positive self-complexity and negative self-complexity. Positive self-complexity was sensitive to methodological factors, namely, variations in stimulus materials used for self-ratings. Negative self-complexity was relatively stable in the face of different rating stimuli and tasks and was related to trait measures of self-evaluation, psychic distress, and psychopathology. These findings were observed and replicated. Higher negative self-complexity was associated with increases in depression symptoms over time. Higher negative self-complexity also predicted a poorer prognosis and less complete recovery from depression in a clinical sample. Results are discussed in light of related research and possible social-cognitive mechanisms.
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Affiliation(s)
- R L Woolfolk
- Department of Psychology, Rutgers-State University of New Jersey, New Brunswick 08903, USA
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Abstract
MARCKS is a protein kinase C (PKC) substrate that is phosphorylated during neurosecretion, phagocyte activation and growth factor-dependent mitogenesis. MARCKS binds calcium/calmodulin and crosslinks F-actin, and both these activities are regulated by PKC-dependent phosphorylation. We present evidence here that PKC-dependent phosphorylation also regulates the cycling of MARCKS between the plasma membrane and Lamp-1-positive lysosomes. Immuno-fluorescence and immunoelectron microscopy, and subcellular fractionation, demonstrated that MARCKS was predominantly associated with the plasma membrane of resting fibroblasts. Activation of PKC resulted in MARCKS phosphorylation and its displacement from the plasma membrane to Lamp-1-positive lysosomes. MARCKS phosphorylation is required for its translocation to lysosomes since mutating either the serine residues phosphorylated by PKC (phos-) or the PKC inhibitor staurosporine, prevented MARCKS phosphorylation, its release from the plasma membrane, and its subsequent association with lysosomes. In the presence of lysosomotropic agents or nocodazole, MARCKS accumulated on lysosomes and returned to the plasma membrane upon drug removal, further suggesting that the protein cycles between the plasma membrane and lysosomes. In contrast to wild-type MARCKS, the phos- mutant did not accumulate on lysosomes in cells treated with NH4Cl, suggesting that basal phosphorylation of MARCKS promotes its constitutive cycling between these two compartments.
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Affiliation(s)
- L A Allen
- Laboratory of Signal Transduction, Rockefeller University, New York, NY 10021, USA
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Allen LA, Zhao XJ, Caughey W, Poyton RO. Isoforms of yeast cytochrome c oxidase subunit V affect the binuclear reaction center and alter the kinetics of interaction with the isoforms of yeast cytochrome c. J Biol Chem 1995; 270:110-8. [PMID: 7814361 DOI: 10.1074/jbc.270.1.110] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [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: 01/27/2023] Open
Abstract
Subunit V, one of the nuclear-coded subunits of yeast cytochrome c oxidase, has two isoforms, Va and Vb. These alter the in vivo intramolecular rates of electron transfer within the holoenzyme (Waterland, R. A., Basu, A., Chance, B., and Poyton, R. O. (1991) J. Biol. Chem. 266, 4180-4186). The isozyme with Vb has a higher turnover rate and a higher intramolecular transfer rate than the isozyme with Va. To determine how these isoforms affect catalysis, we have examined their effects on the binuclear reaction center and on the interaction between cytochrome c oxidase and the two isoforms, iso-1 and iso-2, of yeast cytochrome c. Infrared spectroscopy of carbon monoxide liganded to heme a3 has revealed a single conformer for the binuclear reaction center in the isozyme with Vb but two discrete conformers in the isozyme with Va. The kinetics of interaction for all four pairwise combinations of isozymes with each subunit V isoform and the two cytochrome c isoforms are biphasic, with high and low affinity electron transfer reactions. In general, the isoforms of cytochrome c and subunit V do not alter the Km but do affect the TNmax. The TNmax for isozymes carrying Vb are higher at both high and low affinity sites for each cytochrome c isoform. Iso-1-cytochrome c supports a higher TNmax than Iso-2-cytochrome c. Surprisingly, the combinatorial effect of both sets of isoforms on TNmax is minimized with the pairs of isoforms (iso-1-cytochrome c and subunit Va or iso-2 and subunit Vb) that are co-expressed in cells. Together, these findings support the conclusion that the subunit V isoforms modulate catalysis and suggest that they do so by affecting the environment or structure of the binuclear reaction center. They also suggest that the coexpression of the two cytochrome c isoforms with two subunit V isoforms serves to minimize differences in electron transfer rates brought about by the subunit V isoforms.
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Affiliation(s)
- L A Allen
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309
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Affiliation(s)
- R O Poyton
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309, USA
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Allen LA, Hope L, Raetz CR, Thieringer R. Genetic evidence supporting the role of peroxisome assembly factor (PAF)-1 in peroxisome biogenesis. Polymerase chain reaction detection of a missense mutation in PAF-1 of Chinese hamster ovary cells. J Biol Chem 1994; 269:11734-42. [PMID: 7512952] [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: 01/25/2023] Open
Abstract
The peroxisome/plasmalogen-deficient Chinese hamster ovary (CHO) mutant cell line ZR-78.1 contains a missense mutation in its cDNA-encoding peroxisome assembly factor-1 (PAF-1). Using a rapid polymerase chain reaction assay, we now demonstrate that the genome of ZR-78.1 contains only the mutant allele. When mutant ZR-78.1 is fused with wild-type karyoplasts, occasional "negative nuclear hybrids" are observed that lack peroxisomes (Allen, L.-A. H., Morand, O. H., and Raetz, C. R. H. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 7012-7016). Despite the fact that negative nuclear hybrids are tetraploid, they do not contain the wild-type PAF-1 gene, suggesting that a chromosome fragment bearing the wild-type copy of PAF-1 was lost. Negative nuclear hybrids reconstituted with wild-type cytoplasts do contain a wild-type PAF-1 gene, indicating that the cytoplasts somehow reintroduced the wild-type PAF-1 allele without increasing ploidy. These findings support the role of PAF-1 and exclude the hypothesis of an additional cytoplasmic requirement for reinitiation of peroxisome biogenesis in peroxisome-deficient CHO cells. The plasmalogen deficiency and some other biochemical properties of ZR-78.1 are partially corrected in 5-azacytidine-treated subclones. However, such pseudo-revertants do not contain peroxisomes, consistent with the fact that there is no wild-type PAF-1 gene to reactivate by demethylation.
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Affiliation(s)
- L A Allen
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706
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Alves LC, Allen LA, Houk RS. Measurement of vanadium, nickel, and arsenic in seawater and urine reference materials by inductively coupled plasma mass spectrometry with cryogenic desolvation. Anal Chem 1993; 65:2468-71. [PMID: 8238940 DOI: 10.1021/ac00066a011] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [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: 01/29/2023]
Abstract
Addition of a small dose (2%) of H2 to the aerosol gas flow enhanced analyte signals by a factor of 2-3, which compensated for the loss of analyte signal that accompanied earlier efforts at cryogenic desolvation with inductively coupled plasma mass spectrometry (ICP-MS). Vanadium, nickel, and arsenic at microgram per liter levels in urine, river, and seawater reference materials were determined. The polyatomic ions ClO+, CaO+, and ArCl+, which normally cause severe overlap interferences for these elements, were attenuated to manageable levels by cryogenic desolvation. The samples were simply diluted with 1% HNO3 so that the chloride could be removed as HCl. The analytical results obtained for these standard reference materials agreed closely with the certified or recommended values. The detection limit ranges (3 sigma) obtained were 10-1000 ng L-1 for V, 0.03-20 micrograms L-1 for Ni, and 4-7000 ng L-1 for As in the original samples. The samples were introduced by flow injection to minimize clogging of the sampling orifice.
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Affiliation(s)
- L C Alves
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011
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Abstract
Previous research on the nature of person perception in depression has been inconclusive. This investigation differs from earlier studies in that extensive free-response descriptions of other people and self were collected from patients with major depression and from nonpsychiatric control Ss. In comparison with control Ss, depressed patients described fewer positive aspects not only of self but also of parents and significant others and reported more negative aspects of these people. Cluster analysis (HICLAS) also showed that more cognitive differentiation of negative self-perceptions (negative self-complexity) was characteristic of clinical depression. In both control Ss and patients, a positive (or negative) view of self was highly correlated (.85 or more) with a positive (or negative) view of parents and significant others. These correlations were significantly stronger than those between self and less important others.
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Affiliation(s)
- M A Gara
- University of Medicine and Dentistry, New Jersey Community Mental Health Center, Piscataway 08855-1392
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Allen LA, Raetz CR. Partial phenotypic suppression of a peroxisome-deficient animal cell mutant treated with aminoglycoside G418. J Biol Chem 1992; 267:13191-9. [PMID: 1618823] [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: 12/27/2022] Open
Abstract
Certain enzymes normally associated with peroxisomes, such as the dihydroxyacetone phosphate (DHAP) acyltransferase involved in plasmalogen biosynthesis, are present at low levels in peroxisome-deficient mutants of Chinese hamster ovary (CHO) cells. We now show that the aminoglycoside G418 increases the residual DHAP acyltransferase in mutant ZR-82 by 60-fold. This is accompanied by a dose- and time-dependent restoration of the plasmalogen content. G418 treatment of ZR-82 also increases residual peroxisomal beta-oxidation activity by 3.8-fold. G418 does not affect wild-type CHO cells (CHO-K1) or a different peroxisome-deficient mutant, ZR-78.1. The effects of G418 on ZR-82 are transient, since plasmalogens and DHAP-acyltransferase decline to basal levels 5 days after G418 withdrawal. Other aminoglycosides and lysosomotropic agents do not alter plasmalogen levels in ZR-82. The subcellular distribution of catalase (an enzyme of the peroxisomal matrix which is present in normal amounts in peroxisome-deficient mutants but is mislocalized in the cytosol) is unaffected by G418 treatment of ZR-82, demonstrating that G418 does not restore peroxisomes. Localization of catalase by immunofluorescence microscopy confirms a total absence of intact peroxisomes in ZR-82, either before or after exposure to G418. This study is the first to demonstrate that some peroxisome-deficient mutants can be induced to accumulate functional DHAP acyltransferase and other peroxisomal enzymes, usually missing in the absence of peroxisomes. G418 may have some therapeutic value in selected patients with inborn errors of peroxisome assembly, such as Zellweger syndrome.
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Affiliation(s)
- L A Allen
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706
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Abstract
Chinese hamster ovary (CHO) cells take up and incorporate 9-(1'-pyrene)nonanol (P9OH) into phospholipids and neutral lipids. Exposure of P9OH-labeled cells to long wavelength ultraviolet (UV) light causes cell death, because excitation of the pyrene moiety generates reactive oxygen species. CHO mutant cells deficient in plasmalogen biosynthesis and peroxisome assembly (Zoeller, R.A. and Raetz, C.R.H. (1986) Proc. Natl. Acad. Sci. USA 83, 5170-5174) are much more resistant to P9OH/UV treatment than are wild-type cells. This phenotype is explained by a 7.5-fold reduction of P9OH incorporation into the ethanolamine-linked phospholipids in the mutant cells and 2.4- to 6-fold reduction of P9OH incorporation into all other phospholipids and triglycerides, suggesting a general defect in fatty alcohol metabolism. [U-14C]Hexadecanol incorporation into the phospholipids of the mutant cells is also impaired. In contrast, the fatty acid analog, 9-(1'-pyrene)nonanoic acid, is incorporated into cells two times more rapidly by the mutants than by the wild type. Resistance to P9OH/UV treatment affords a simple, new method for the selection of animal cell mutants defective in peroxisome biogenesis.
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Affiliation(s)
- O H Morand
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison
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Zoeller RA, Allen LA, Santos MJ, Lazarow PB, Hashimoto T, Tartakoff AM, Raetz CR. Chinese hamster ovary cell mutants defective in peroxisome biogenesis. Comparison to Zellweger syndrome. J Biol Chem 1989; 264:21872-8. [PMID: 2689450] [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
We have previously reported the isolation of Chinese hamster ovary (CHO) cell mutants that are defective in the biosynthesis of plasmalogens, deficient in at least two peroxisomal enzymes (dihydroxyacetonephosphate (DHAP) acyltransferase and alkyl-DHAP synthase), and in which catalase is not found within peroxisomes (Zoeller, R. A., and Raetz, C. R. H. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 5170). We now provide further evidence that three such strains are more generally defective in peroxisome biogenesis. Electron microscopic cytochemistry revealed that the mutants did not contain recognizable peroxisomes. However, immunofluorescence microscopy using an antibody directed against peroxisomal integral membrane proteins revealed the presence of peroxisomal membrane ghosts resembling those seen in cells of patients suffering from one of the human peroxisomal disorders, Zellweger syndrome. Immunoblot analyses, using antibodies specific for peroxisomal matrix proteins, demonstrated deficiencies of peroxisomal proteins in the mutant CHO cells that were similar to those in Zellweger syndrome. Fusion of a CHO mutant with fibroblasts obtained from Zellweger patients resulted in restoration of peroxisomal dihydroxyacetonephosphate acyltransferase and peroxisomal acyl-coenzyme A oxidation activities. The hybrid cells also regained the ability to synthesize plasmenylethanolamine. Moreover, normal peroxisomes were seen by immunofluorescence in the hybrid cells. These results indicate that the hybrid cells have recovered the ability to assemble peroxisomes and that, although the mutant CHO cells are biochemically and morphologically very similar to cells from patients with Zellweger syndrome, the genetic lesions are distinct. Our somatic cell mutants should be useful in identifying factors and genes involved in peroxisome biogenesis and may aid the genetic categorization of the various peroxisomal disorders.
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Affiliation(s)
- R A Zoeller
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706
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Abstract
Hybrids constructed by fusion of wild-type Chinese hamster ovary cells (CHO-K1) to peroxisome-deficient CHO mutants (ZR-78.1) contain normal peroxisomes, demonstrating that the mutation(s) are recessive. "Nuclear hybrids" prepared by fusion of CHO-K1 karyoplasts to mutant ZR-78.1 occasionally fail to regain intact peroxisomes (approximately 1/300 cells). These peroxisome-deficient nuclear hybrids closely resemble the original mutant cells by biochemical criteria, but their modal chromosome number is 36-38, the same as that of CHO hybrids generated from intact cells. When the peroxisome-deficient nuclear hybrids are fused to wild-type cytoplasts, a fraction of the fusion products (at least 70%) continue to propagate normal peroxisomes indefinitely. Peroxisome biogenesis cannot be reinitiated in cells of mutant ZR-78.1 by fusion to wild-type cytoplasts. Our results suggest that a wild-type nucleus by itself is necessary but not sufficient for restoration of normal peroxisome biogenesis and that a cytoplasmic component of wild-type cells, possibly a normal peroxisome, is also required.
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Affiliation(s)
- L A Allen
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706
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