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Baker DJ, Clarke RH, McGeoch MA. The power to detect regional declines in common bird populations using continental monitoring data. Ecol Appl 2019; 29:e01918. [PMID: 31162764 DOI: 10.1002/eap.1918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/08/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
Anthropogenic environmental change is driving the rapid loss of biodiversity. Large declines in the abundance of historically common species are now emerging as a major concern. Identifying declining populations through long-term biodiversity monitoring is vital for implementing timely conservation measures. It is, therefore, critical to evaluate the likelihood that persistent long-term population trends of a given size could be detected using existing monitoring data and methods. Here, we test the power to detect declines in Australia's common landbirds using long-term citizen science monitoring. We use spatially explicit simulations of occupancy dynamics and virtual sampling, designed to mimic bird monitoring in better-sampled regions of Australia, to assess likely power in these data to detect trends relevant for conservation. We predict the statistical power for 326 common species that meet minimum requirements for monitoring data across 10 regions of Australia, estimating the number of species for which we would have a high (≥80%) chance of detecting declines of different sizes. The power to detect declines of ≥30% per decade was predicted to be high for at least one-third of the common species in 7 of 10 regions, with a total of 103 (32% of 326) unique species sufficiently monitored in at least one region. These species spanned 12 taxonomic orders, four orders of magnitude in body mass, and a broad diversity of dietary guilds, suggesting the current species pool will likely serve as robust indicators for a broad range of environmental states and pressures. Power was strongly affected by species' detectability, and power to detect even large declines was negligible when species are detected on ≤50% of visits to an occupied site. Predicted power for many species fell just short of the 80% threshold in one or more regions, which suggests an increase in effort targeting these species could greatly enhance the species and regional representation of these data. Against the backdrop of unprecedented biodiversity losses, this study shows how critical evaluation of existing monitoring schemes is valuable both for assessing the contribution of citizen science schemes to biodiversity monitoring and for designing strategic monitoring to significantly improve the knowledge these schemes provide.
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Affiliation(s)
- D J Baker
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - R H Clarke
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - M A McGeoch
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
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Goodall EF, Wang C, Simpson JE, Baker DJ, Drew DR, Heath PR, Saffrey MJ, Romero IA, Wharton SB. Age-associated changes in the blood-brain barrier: comparative studies in human and mouse. Neuropathol Appl Neurobiol 2017; 44:328-340. [PMID: 28453876 PMCID: PMC5900918 DOI: 10.1111/nan.12408] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [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: 02/13/2017] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 12/22/2022]
Abstract
Aims While vascular pathology is a common feature of a range of neurodegenerative diseases, we hypothesized that vascular changes occur in association with normal ageing. Therefore, we aimed to characterize age‐associated changes in the blood–brain barrier (BBB) in human and mouse cohorts. Methods Immunohistochemistry and Evans blue assays were used to characterize BBB dysfunction (tight junction protein expression and serum plasma protein accumulation), vascular pathology (pericyte loss and vascular density) and glial pathology (astrocyte and microglial density) in ageing neurological control human prefrontal cortex (a total of 23 cases from 5 age groups representing the spectrum of young adult to old age: 20–30 years, 31–45 years, 46–60 years, 61–75 years and 75+) and C57BL/6 mice (3 months, 12 months, 18 months and 24 months, n = 5/6 per group). Results Quantification of the tight junction protein ZO‐1 within the cortex and cerebellum of the mouse cohort showed a significant trend to both increased number (cortex P < 0.001, cerebellum P < 0.001) and length (cortex P < 0.001, cerebellum P < 0.001) of junctional breaks associated with increasing age. GFAP expression significantly correlated with ageing in the mice (P = 0.037). In the human cohort, assessment of human protein accumulation (albumin, fibrinogen and human IgG) demonstrated cells morphologically resembling clasmatodendritic astrocytes, indicative of BBB dysfunction. Semiquantitative assessment of astrogliosis in the cortex expression revealed an association with age (P = 0.003), while no age‐associated changes in microglial pathology, microvascular density or pericyte coverage were detected. Conclusions This study demonstrates BBB dysfunction in normal brain ageing, both in human and mouse cohorts.
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Affiliation(s)
- E F Goodall
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, UK
| | - C Wang
- School of Life Science, Health and Chemical Sciences, Faculty of Science, The Open University, Milton Keynes, UK
| | - J E Simpson
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, UK
| | - D J Baker
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, UK
| | - D R Drew
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, UK
| | - P R Heath
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, UK
| | - M J Saffrey
- School of Life Science, Health and Chemical Sciences, Faculty of Science, The Open University, Milton Keynes, UK
| | - I A Romero
- School of Life Science, Health and Chemical Sciences, Faculty of Science, The Open University, Milton Keynes, UK
| | - S B Wharton
- Sheffield Institute for Translational Neuroscience, The University of Sheffield, Sheffield, UK
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Baker DJ, Wilkinson GP, Atkinson AM, Jones HB, Coghlan M, Charles AD, Leighton B. Chronic glucokinase activator treatment at clinically translatable exposures gives durable glucose lowering in two animal models of type 2 diabetes. Br J Pharmacol 2014; 171:1642-54. [PMID: 24772484 DOI: 10.1111/bph.12504] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Pharmacological activation of glucokinase (GK) lowers blood glucose in animal models and humans, confirming proof of concept for this mechanism. However, recent clinical evidence from chronic studies suggests that the glucose-lowering effects mediated by glucokinase activators (GKAs) are not maintained in patients with type 2 diabetes (T2D). Existing preclinical data with GKAs do not explain this loss of sustained glucose-lowering efficacy in patients. Here, we have assessed the effects of chronic (up to 11 months) treatment with two different GKAs in two models of T2D. EXPERIMENTAL APPROACH Two validated animal models of T2D, insulin-resistant obese Zucker rats and hyperglycaemic gk(wt/del) mice, were treated with two different GKAs for 1 or 11 months respectively at exposures that translate to clinical exposures in humans. Blood glucose, cholesterol, triglycerides and insulin were measured. GKA pharmacokinetics were also determined. KEY RESULTS Treatment with either GKA provided sustained lowering of blood glucose for up to 1 month in the Zucker rat and up to 11 months in hyperglycaemic gk(wt/del) mice, with maintained compound exposures. This efficacy was achieved without increases in plasma or hepatic triglycerides, accumulation of hepatic glycogen or impairment of glucose-stimulated insulin secretion. CONCLUSIONS AND IMPLICATIONS Chronic treatment with two GKAs in two animal models of diabetes provided sustained lowering of blood glucose, in marked contrast to clinical findings. Therefore, either these animal models of T2D are not good predictors of responses in human T2D or we need a better understanding of the consequences of GK activation in humans.
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Baker DJ, Atkinson AM, Wilkinson GP, Coope GJ, Charles AD, Leighton B. Characterization of the heterozygous glucokinase knockout mouse as a translational disease model for glucose control in type 2 diabetes. Br J Pharmacol 2014; 171:1629-41. [PMID: 24772483 DOI: 10.1111/bph.12498] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE The global heterozygous glucokinase (GK) knockout (gk(wt/del)) male mouse, fed on a high-fat (60% by energy) diet, has provided a robust and reproducible model of hyperglycaemia. This model could be highly relevant to some facets of human type 2 diabetes (T2D). We aimed to investigate the ability of standard therapeutic agents to lower blood glucose at translational doses, and to explore the glucose-lowering potential of novel glucokinase activators (GKAs) in this model. EXPERIMENTAL APPROACH We measured the ability of insulin, metformin, glipizide, exendin-4 and sitagliptin, after acute or repeat dose administration, to lower free-feeding glucose levels in gk(wt/del) mice. Further, we measured the ability of novel GKAs, GKA23, GKA71 and AZD6370 to control glucose either alone or in combination with some standard agents. KEY RESULTS A single dose of insulin (1 unit·kg(-1)), metformin (150, 300 mg·kg(-1)), glipizide (0.1, 0.3 mg·kg(-1)), exendin-4 (2, 20 μg·kg(-1)) and GKAs reduced free-feeding glucose levels. Sitagliptin (10 mg·kg(-1)), metformin (300 mg·kg(-1)) and AZD6370 (30, 400 mg·kg(-1)) reduced glucose excursions on repeat dosing. At a supra-therapeutic dose (400 mg·kg(-1)), AZD6370 also lowered basal levels of glucose without inducing hypoglycaemia. CONCLUSION AND IMPLICATIONS Standard glucose-lowering therapeutic agents demonstrated significant acute glucose lowering in male gk(wt/del) mice at doses corresponding to therapeutic free drug levels in man, suggesting the potential of these mice as a translatable model of human T2D. Novel GKAs also lowered glucose in this mouse model.
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Abstract
Aging is the main risk factor for most chronic diseases, disabilities, and declining health. It has been proposed that senescent cells--damaged cells that have lost the ability to divide--drive the deterioration that underlies aging and age-related diseases. However, definitive evidence for this relationship has been lacking. The use of a progeroid mouse model (which expresses low amounts of the mitotic checkpoint protein BubR1) has been instrumental in demonstrating that p16(Ink4a)-positive senescent cells drive age-related pathologies and that selective elimination of these cells can prevent or delay age-related deterioration. These studies identify senescent cells as potential therapeutic targets in the treatment of aging and age-related diseases. Here, we describe how senescent cells develop, the experimental evidence that causally implicates senescent cells in age-related dysfunction, the chronic diseases and disorders that are characterized by the accumulation of senescent cells at sites of pathology, and the therapeutic approaches that could specifically target senescent cells.
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Affiliation(s)
- R M Naylor
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
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Bridges PJ, Jeoung M, Kim H, Kim JH, Lee DR, Ko C, Baker DJ. Methodology Matters: In Vitro Fertilization Versus Intracytoplasmic Sperm Injection and Embryonic Gene Expression in the Mouse. Biol Reprod 2011. [DOI: 10.1093/biolreprod/85.s1.742] [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: 11/14/2022] Open
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Bridges PJ, Jeoung M, Kim H, Kim JH, Lee DR, Ko C, Baker DJ. Methodology matters: IVF versus ICSI and embryonic gene expression. Reprod Biomed Online 2011; 23:234-44. [PMID: 21665548 DOI: 10.1016/j.rbmo.2011.04.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/09/2011] [Accepted: 04/14/2011] [Indexed: 12/20/2022]
Abstract
The use of assisted reproduction treatment, especially intracytoplasmic sperm injection (ICSI), is now linked to a range of adverse consequences, the aetiology of which remains largely undefined. Our objective of this study was to determine differences in gene expression of blastocysts generated by ICSI as well as ICSI with artificial oocyte activation (ICSI-A) versus the less manipulative IVF, providing fundamental genetic information that can be used to aid in the diagnosis or treatment of those adversely affected by assisted reproduction treatment, as well as stimulate research to further refine these techniques. Murine blastocysts were generated by ICSI, ICSI-A and IVF, and processed for a microarray-based analysis of gene expression. Ten blastocysts were pooled for each procedure and three independent replicates generated. The data were then processed to determine differential gene expression and to identify biological pathways affected by the procedures. In blastocysts derived by ICSI versus IVF, the expression of 197 genes differed (P < 0.01). In blastocysts derived by ICSI-A versus IVF and ICSI-A versus ICSI, the expression of 132 and 65 genes differed respectively (P < 0.01). Procedural-induced changes in genes regulating specific biological pathways revealed some consistency to known adverse consequences. Detailed investigation of procedure-specific dysfunction is therefore warranted.
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Affiliation(s)
- Phillip J Bridges
- Division of Clinical and Reproductive Sciences, University of Kentucky, Lexington, KY 40536, USA
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Gardiner SM, March JE, Kemp PA, Bennett T, Baker DJ. Possible involvement of GLP-1(9-36) in the regional haemodynamic effects of GLP-1(7-36) in conscious rats. Br J Pharmacol 2010; 161:92-102. [PMID: 20718742 DOI: 10.1111/j.1476-5381.2010.00867.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE The incretin hormone, glucagon-like peptide (GLP)-1(7-36), is rapidly cleaved by dipeptidyl peptidase 4 (DPP-4) into GLP-1(9-36), and although it is agreed that most, if not all, of the metabolic effects are attributable to the intact peptide, the degree to which the cardiovascular effects are due to the cleavage product is unclear. The purpose of this study was to measure the regional haemodynamic effects of GLP-1(7-36), and determine the extent to which the cardiovascular effects of GLP-1(7-36) were influenced by DPP-4 inhibition and reproduced by GLP-1(9-36). Additional experiments investigated the involvement of autonomic mechanisms in the cardiovascular effects of GLP-1(7-36). EXPERIMENTAL APPROACH Regional haemodynamic effects of bolus doses and 4 h infusions of GLP-1(7-36) amide and GLP-1(9-36) amide were measured in conscious, chronically instrumented rats; the influence of DPP-4 inhibition and autonomic blockade on responses to GLP-1(7-36) were also assessed. KEY RESULTS Glucagon-like peptide-1(7-36) had clear regional haemodynamic effects comprising tachycardia, a rise in blood pressure, renal and mesenteric vasoconstriction and hindquarters vasodilatation, whereas GLP-1(9-36) was devoid of any cardiovascular actions. The effects of GLP-1(7-36) were enhanced by DPP-4 inhibition, and the tachycardia and hindquarters vasodilatation were beta-adrenoceptor-mediated. CONCLUSIONS AND IMPLICATIONS In conscious rats, the cardiovascular effects of GLP-1(7-36) resemble those of the GLP analogue, exendin-4, and are attributable to the intact peptide rather than the cleavage product, GLP-1(9-36).
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Affiliation(s)
- S M Gardiner
- School of Biomedical Sciences, University of Nottingham, Nottingham, UK.
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Allen CG, Baker DJ, Albin JM, Oertli HE, Gillaspie DT, Olson DC, Furtak TE, Collins RT. Surface modification of ZnO using triethoxysilane-based molecules. Langmuir 2008; 24:13393-13398. [PMID: 18973351 DOI: 10.1021/la802621n] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Zinc oxide (ZnO) is an important material for hybrid inorganic-organic devices in which the characteristics of the interface can dominate both the structural and electronic properties of the system. These characteristics can be modified through chemical functionalization of the ZnO surface. One of the possible strategies involves covalent bonding of the modifier using silane chemistry. Whereas a significant body of work has been published regarding silane attachments to glass and SiO2, there is less information about the efficacy of this method for controlling the surface of metal oxides. Here we report our investigation of molecular layers attached to polycrystalline ZnO through silane bonding, controlled by an amine catalyst. The catalyst enables us to use triethoxysilane precursors and thereby avoid undesirable multilayer formation. The polycrystalline surface is a practical material, grown by sol-gel processing, that is under active exploration for device applications. Our study included terminations with alkyl and phenyl groups. We used water contact angles, infrared spectroscopy, and X-ray photoemission spectroscopy to evaluate the modified surfaces. Alkyltriethoxysilane functionalization of ZnO produced molecular layers with submonolayer coverage and evidence of disorder. Nevertheless, a very stable hydrophobic surface with contact angles approaching 106 degrees resulted. Phenyltriethoxysilane was found to deposit in a similar manner. The resulting surface, however, exhibited significantly different wetting as a result of the nature of the end group. Molecular layers of this type, with a variety of surface terminations that use the same molecular attachment scheme, should enable interface engineering that optimizes the chemical selectivity of ZnO biosensors or the charge-transfer properties of ZnO-polymer interfaces found in oxide-organic electronics.
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Affiliation(s)
- C G Allen
- Department of Physics, Colorado School of Mines, Golden, Colorado, USA
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Abstract
Orderly progression through mitosis is regulated by the anaphase-promoting complex/cyclosome (APC/C), a large multiprotein E3 ubiquitin ligase that targets key mitotic regulators for destruction by the proteasome. APC/C has two activating subunits, Cdc20 and Cdh1. The well-established view is that Cdc20 activates APC/C from the onset of mitosis through the metaphase-anaphase transition, and that Cdh1 does so from anaphase through G1. Recent work, however, indicates that Cdh1 also activates APC/C in early mitosis and that this APC/C pool targets the anaphase inhibitor securin. To prevent premature degradation of securin, the nuclear transport factors Nup98 and Rae1 associate with APC/C(Cdh1)-securin complexes. In late metaphase, when all kinetochores are attached to spindle microtubules and the spindle assembly checkpoint is satisfied, Nup98 and Rae1 are released from these complexes, thereby allowing for prompt ubiquitination of securin by APC/C(Cdh1). This, and other mechanisms by which the catalytic activity of APC/C is tightly regulated to ensure proper timing of degradation of each of its mitotic substrates, are highlighted.
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Affiliation(s)
- D J Baker
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Baker DJ. Semen analysis. Clin Lab Sci 2007; 20:172-87; quiz 188-92. [PMID: 17691673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- Doris J Baker
- Center of Excellence in Reproductive Sciences, University of Kentucky, Lexington, KY 40536-0200, USA.
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Jones SW, Baker DJ, Gardiner SM, Bennett T, Timmons JA, Greenhaff PL. The Effect of the β2-Adrenoceptor Agonist Prodrug BRL-47672 on Cardiovascular Function, Skeletal Muscle Myosin Heavy Chain, and MyoD Expression in the Rat. J Pharmacol Exp Ther 2004; 311:1225-31. [PMID: 15243031 DOI: 10.1124/jpet.104.071589] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [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: 11/22/2022] Open
Abstract
The intracellular mechanisms that regulate changes in postnatal myosin heavy chain (MHC) expression are not well established. The major objective of this study was to examine the acute and chronic effects of administration of BRL-47672, the prodrug of the beta2-adrenoceptor agonist clenbuterol on MHC and MyoD transcription factor expression to determine whether or not changes in MHC composition are preceded by changes in MyoD protein expression. To assess to what extent the use of BRL-47672 minimized cardiovascular effects, its hemodynamic actions were compared with those of clenbuterol. The effect of BRL-47672 on heart rate, mean arterial blood pressure, and hindquarters vascular conductance was significantly less than that of clenbuterol after a single i.p. injection (250 microg kg(-1) body mass). In the main study, 4-week old rats were given BRL-47672 (900 microg kg(-1) body mass) or an equivalent volume of saline (control) daily for 1, 28, or 56 days. Soleus muscle (SOL) was excised and MHC and MyoD expression analyzed. After 4 weeks, SOL from the BRL-47672-treated animals had significantly faster MHC composition (49 +/- 2% MHCIIA) compared with those from the control animal (39 +/- 3% MHCIIA, P <0.05). MyoD expression increased by 40% after 1 day of BRL-47672 administration (P <0.05) before a change in MHC composition. In conclusion, these data suggest that increased expression of fast-type MHCIIA expression in rat SOL induced by BRL-47672 administration is preceded by changes in the level of MyoD transcription factor expression.
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Affiliation(s)
- S W Jones
- Centre for Integrated Systems Biology and Medicine, Queens Medical Centre, University of Nottingham, Nottingham, NG7 2UH, UK
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Scaramuzzi RJ, Baker DJ. Possible therapeutic benefits of adenosine-potentiating drugs in reducing age-related degenerative disease in dogs and cats. J Vet Pharmacol Ther 2003; 26:327-35. [PMID: 14633184 DOI: 10.1046/j.1365-2885.2003.00527.x] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Adenosine is a ubiquitous, biologically important molecule that is a precursor of other biologically active molecules. It also is a component of some co-factors and has distinct physiological actions in its own right. Levels are maintained by synthesis from dietary precursors and re-cycling. The daily turnover of adenosine is very high. Adenosine can act either as a hormone by binding to adenosine receptors, four adenosine receptor subtypes have been identified, and as an intracellular modulator, after transport into the cell by membrane transporter proteins. One of the principal intracellular actions of adenosine is inhibition of the enzyme phosphodiesterase. Extracellular adenosine also has specific neuromodulatory actions on dopamine and glutamate. Selective and nonselective agonists and antagonists of adenosine are available. The tasks of developing, evaluating and exploiting the therapeutic potential of these compounds is still in its infancy. Adenosine has actions in the central nervous system (CNS), heart and vascular system, skeletal muscle and the immune system and the presence of receptors suggests potential actions in the gonads and other organs. Adenosine agonists improve tissue perfusion through actions on vascular smooth muscle and erythrocyte fluidity and they can be used to improve the quality of life in aged dogs. This article reviews the therapeutic potential of adenosine-potentiating drugs in the treatment of age-related conditions in companion animals, some of which may be exacerbated by castration or spaying at an early age.
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Affiliation(s)
- R J Scaramuzzi
- Department of Veterinary Basic Sciences, Royal Veterinary College, London, UK.
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Baker DJ, Jeram J, Reid LA. Failure of the vaccine cold chain following modification of a domestic refrigerator. N Z Med J 2002; 115:U251. [PMID: 12552292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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Ribes JA, Smith A, Hayes M, Baker DJ, Winters JL. Comparative performance of herpes simplex virus type 1-specific serologic assays from MRL and Meridian Diagnostics. J Clin Microbiol 2002; 40:1071-2. [PMID: 11880443 PMCID: PMC120264 DOI: 10.1128/jcm.40.3.1071-1072.2002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [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: 11/20/2022] Open
Abstract
Two companies, MRL and Meridian Diagnostics, have developed Food and Drug Administration-approved herpes simplex virus type 1 type-specific enzyme immunoassays. The sensitivity, specificity, and overall testing efficiency of these assays were 98.2, 93.8, and 96.6% for MRL and 98.8, 99.0, and 98.1% for Meridian, making both of these kits suitable for use in the clinical lab.
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Affiliation(s)
- Julie A Ribes
- Department of Clinical Sciences, University of Kentucky, Lexington, Kentucky 40536-0298, USA.
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Ribes JA, Hayes M, Smith A, Winters JL, Baker DJ. Comparative performance of herpes simplex virus type 2-specific serologic assays from Meridian Diagnostics and MRL diagnostics. J Clin Microbiol 2001; 39:3740-2. [PMID: 11574606 PMCID: PMC88422 DOI: 10.1128/jcm.39.10.3740-3742.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MRL Diagnostics and Meridian Diagnostics have recently designed herpes simplex virus type 2 (HSV-2)-specific enzyme immunoassays for HSV-2 antibody detection. Blood donor sera were assayed for HSV-2 antibodies by both methods. The sensitivity, specificity, and efficiency were 97.9, 95.4, and 95.9% for the MRL assay and 83.2, 98.2, and 95.5% for the Meridian assay, respectively.
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Affiliation(s)
- J A Ribes
- Department of Clinical Laboratory Sciences, University of Kentucky, Lexington, Kentucky 40536-0298, USA.
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Ribes JA, Steele AD, Seabolt JP, Baker DJ. Six-year study of the incidence of herpes in genital and nongenital cultures in a central Kentucky medical center patient population. J Clin Microbiol 2001; 39:3321-5. [PMID: 11526170 PMCID: PMC88338 DOI: 10.1128/jcm.39.9.3321-3325.2001] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [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: 11/20/2022] Open
Abstract
Herpes infections are among the most common sexually transmitted diseases and are the most common cause of genital ulcer disease in the United States. This study addresses the changing distribution of herpes simplex virus type 1 (HSV-1) and HSV-2 in patients presenting for evaluation of herpetic infections. Viral culture results from the University of Kentucky Clinical Microbiology Laboratory were reviewed for a 6-year period (1994 through 1999). Data were collected on patient sex, site of culture, and culture result. These data were analyzed statistically to identify yearly trends. Of the 4,498 cultures analyzed, nearly equal proportions of HSV-1 (13.3%) and HSV-2 (12.0%) were detected for an overall culture positivity rate of 25.3%. Approximately two-thirds of all positive cultures were from women. Although HSV-2 remained the predominant type of genital herpes, over the 6-year span of this study, there was a trend toward increasing proportions of HSV-1 genitalis, with 31.8% of male patients and 44.8% of female patients demonstrating HSV-1 genitalis by 1999. The majority of patients with HSV in nongenital sites grew HSV-1. Although there was significant yearly variation, HSV-2 was isolated from only 9.4% of patients with nongenital HSV for the entire 6-year period. This study therefore concludes that HSV-2 remains primarily a genital pathogen, while HSV-1 is taking on an increasingly important role in causing genital ulcer disease in addition to being the primary nongenital HSV.
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Affiliation(s)
- J A Ribes
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, Kentucky 40536-0298, USA.
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Generini S, Matucci-Cerinic M, Partsch G, Stancikova M, Pignone A, Konttinen YT, Rovensky J, Baker DJ, Schumacher HR. Evidence for hyaluronan production in the air pouch model in rats. Clin Exp Rheumatol 2001; 19:271-6. [PMID: 11407079] [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: 02/20/2023]
Abstract
OBJECTIVE The aim of our work was to investigate the presence of hyaluronan (HA) in the rat air pouch and its behaviour in response to inflammatory stimuli. METHODS HA levels (by a microplate assay) and the leucocyte count were determined in the fluid obtained from air pouches in which acute or subacute inflammation had been induced by the injection of monosodium urate crystals (MSU) or high density polyethylene (HDPE) debris respectively and in relative controls. RESULTS In control pouches of both groups, remarkable levels of HA were found; these levels were higher in the very first hours (2475 and 1850 micrograms/l at 6 hrs) and then gradually decreased. In pouches injected with MSU, HA moderately increased (p < 0.001) after 6 hrs, reached a peak after 12 hrs (p < 0.001) and began to taper at 24 hrs (p < 0.001). The leucocyte count was also increased at 6 hrs (p < 0.001), became higher at 12 hrs (p < 0.001) and tapered at 24 hrs (p < 0.001). In the HDPE pouches, HA levels were significantly reduced with respect to controls after 6 hours (p < 0.001), increasing later (p < 0.001) to reach a peak at 24 hrs (p < 0.001), and returning to the original levels, or even below, in the following 72 hours. CONCLUSIONS These data confirm that the pouch lining produces fair amounts of HA and provide evidence that, in this system, HA levels seem to be influenced by the degree of inflammation even if with variable behaviour in relation to the different characteristics and phases of phlogosis. The present data suggest that the air pouch is a useful experimental model for studies on HA metabolism in either acute or chronic inflammation.
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Affiliation(s)
- S Generini
- Department of Internal Medicine, Section of Rheumatology, University of Florence, Italy.
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Abstract
Hazardous materials (HAZMAT) carry many inherent dangers. Such materials are distributed widely in industrial and military sites. Toxic trauma (TT) denotes the complex of systemic and organ injury caused by toxic agents. Often, TT is associated with other injuries that also require the application of life-support techniques. Rapid onset of acute respiratory failure and consequent cardiovascular failure are of primary concern. Management of TT casualties is dependent upon the characteristics of the toxic agents involved and on the demographics surrounding the HAZMAT incident. Agents that can produce TT possess two pairs of salient characteristics: (1) causality (toxicity and latency), and (2) EMS system (persistency and transmissibility). Two characteristics of presentations are important: (1) incident presentation, and (2) casualty presentation. In addition, many of these agents complicate the processes associated with anaesthesia and must be dealt with. Failure of recognition of these factors may result in the development of respiratory distress syndromes and multiorgan system failure, or even death.
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Affiliation(s)
- T M Moles
- Oral and Maxillofacial Surgery, University of Hong Kong, China
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Abstract
A descriptive assessment of environmental variables influencing patterns of staff communication with people living in three community-based residential facilities supporting persons with disabilities was presented. Each of the 16 participating staff persons was observed for 2 hours, and all resident-directed communication behaviors were coded according to staff person, activity context, and resident. Statistical analyses were performed examining frequencies of interaction across these variables. Frequencies of communication were found to differ across activities and residents (communicative partners), but not staff persons or homes. Directions for future research and clinical implications are given, including the development of a model of staff performance and the creation of self-reinforcing social communities in residential settings for persons with disabilities.
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Affiliation(s)
- D J Baker
- Oregon Rehabilitation Association, USA
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Baker DJ. Performing a quality semen analysis in the clinical laboratory. MLO Med Lab Obs 2000; 32:20-9; quiz 30-1. [PMID: 11193972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- D J Baker
- University of Kentucky, Lexington, KY, USA
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Newton JR, Lakhani KH, Wood JL, Baker DJ. Risk factors for equine influenza serum antibody titres in young thoroughbred racehorses given an inactivated vaccine. Prev Vet Med 2000; 46:129-41. [PMID: 10878300 DOI: 10.1016/s0167-5877(00)00144-6] [Citation(s) in RCA: 29] [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: 10/18/2022]
Abstract
Young Thoroughbred racehorses (222 yearlings entering training and 246 2-year-old horses already in training) from eight flat-training yards in Newmarket, UK were used to monitor serological responses to vaccination with an inactivated influenza virus vaccine. Blood samples taken prior to and after vaccination were tested by single radial haemolysis (SRH) to determine antibody titres (expressed as area of haemolysis in mm(2)). Prior to vaccination, yearlings had mean antibody titres (64+/-4 mm(2)) that were approximately half of those of 2-year-olds (115+/-3 mm(2)) and 89% of yearlings and 73% of 2-year-olds had SRH titres <140 mm(2). Extrapolation from experimental and field studies suggests that these levels would not protect against homologous influenza virus infection. Both age-groups showed anamnestic responses to vaccination resulting in similar peak mean titres ( approximately 160+/-2mm(2)) with 67% of yearlings and 73% of 2-year-olds achieving levels > or =140 mm(2). A second dose of vaccine administered a month after the first in yearlings did not increase the mean titre but 75% of horses had levels of antibody > or =140 mm(2). The vaccination history in the official passport of yearlings showed that 23% had no record of previous vaccination and were probably fully susceptible to infection. For yearlings entering training, the important predictors from multiple-regression analyses of SRH titres prior to vaccination were "Time since last vaccination," "Total number of previous vaccines" and "Age at first vaccination." In 2-year-olds and following two doses of vaccine in yearlings, there was no significant relationship between these factors and SRH titre.
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Affiliation(s)
- J R Newton
- Epidemiology Unit, Animal Health Trust, Lanwades Park, Kentford, Suffolk CB8 0NG, Newmarket, UK.
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Abstract
The Zygomycetes represent relatively uncommon isolates in the clinical laboratory, reflecting either environmental contaminants or, less commonly, a clinical disease called zygomycosis. There are two orders of Zygomycetes containing organisms that cause human disease, the Mucorales and the Entomophthorales. The majority of human illness is caused by the Mucorales. While disease is most commonly linked to Rhizopus spp., other organisms are also associated with human infection, including Mucor, Rhizomucor, Absidia, Apophysomyces, Saksenaea, Cunninghamella, Cokeromyces, and Syncephalastrum spp. Although Mortierella spp. do cause disease in animals, there is no longer sufficient evidence to suggest that they are true human pathogens. The spores from these molds are transmitted by inhalation, via a variety of percutaneous routes, or by ingestion of spores. Human zygomycosis caused by the Mucorales generally occurs in immunocompromised hosts as opportunistic infections. Host risk factors include diabetes mellitus, neutropenia, sustained immunosuppressive therapy, chronic prednisone use, iron chelation therapy, broad-spectrum antibiotic use, severe malnutrition, and primary breakdown in the integrity of the cutaneous barrier such as trauma, surgical wounds, needle sticks, or burns. Zygomycosis occurs only rarely in immunocompetent hosts. The disease manifestations reflect the mode of transmission, with rhinocerebral and pulmonary diseases being the most common manifestations. Cutaneous, gastrointestinal, and allergic diseases are also seen. The Mucorales are associated with angioinvasive disease, often leading to thrombosis, infarction of involved tissues, and tissue destruction mediated by a number of fungal proteases, lipases, and mycotoxins. If the diagnosis is not made early, dissemination often occurs. Therapy, if it is to be effective, must be started early and requires combinations of antifungal drugs, surgical intervention, and reversal of the underlying risk factors. The Entomophthorales are closely related to the Mucorales on the basis of sexual growth by production of zygospores and by the production of coenocytic hyphae. Despite these similarities, the Entomophthorales and Mucorales have dramatically different gross morphologies, asexual reproductive characteristics, and disease manifestations. In comparison to the floccose aerial mycelium of the Mucorales, the Entomophthorales produce a compact, glabrous mycelium. The asexually produced spores of the Entomophthorales may be passively released or actively expelled into the environment. Human disease with these organisms occurs predominantly in tropical regions, with transmission occurring by implantation of spores via minor trauma such as insect bites or by inhalation of spores into the sinuses. Conidiobolus typically infects mucocutaneous sites to produce sinusitis disease, while Basidiobolus infections occur as subcutaneous mycosis of the trunk and extremities. The Entomophthorales are true pathogens, infecting primarily immunocompetent hosts. They generally do not invade blood vessels and rarely disseminate. Occasional cases of disseminated and angioinvasive disease have recently been described, primarily in immunocompromised patients, suggesting a possible emerging role for this organism as an opportunist.
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Affiliation(s)
- J A Ribes
- Departments of Pathology and Laboratory Medicine and of Clinical Laboratory Sciences, University of Kentucky, Lexington, KY 40536-0084, USA.
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Baker DJ. The immediate care of casualties following the release of toxic chemicals. Resuscitation 1999; 42:101-2. [PMID: 10617328 DOI: 10.1016/s0300-9572(99)00095-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Abstract
Mass release of toxic substances may occur either accidentally or deliberately in both peace and war. Different approaches to the management of casualties from such an event have been developed by civil and military emergency medical teams, and reflect the different circumstances in which they operate. The nature and classification of toxic hazards is considered and the civil and military operational and medical responses compared. Both systems have different aspects that can contribute to early casualty management in a contaminated environment.
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Affiliation(s)
- D J Baker
- SAMU de Paris, Hôpital Necker Enfants-Malades, France
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Abstract
Accidental or deliberate release of toxic substances may be a cause of mass casualties, some of which may involve partial or complete respiratory failure. Life support measures may be delayed by the need for containment of the toxic release and decontamination. Advanced life support (ALS) may be provided in such circumstances using the TOXALS protocol. With proper training and equipment, emergency medical personnel can provide effective prehospital care during decontamination of chemical casualties.
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Affiliation(s)
- D J Baker
- SAMU de Paris, Hôpital Necker Enfants-Malades, France
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30
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Abstract
The management of injuries from toxic release (HAZMAT) incidents is unfamiliar to many emergency medical responders owing to the relative rarity of such incidents. However, the risks from toxic release in both industrial and other metropolitan areas are increasing and emergency medical services (EMS) personnel should be trained to be aware of the dangers to both victims and responders alike. Many examples exist of analogies for the management of HAZMAT situations from conventional prehospital and hospital emergency medicine. Application of the lessons learned in more familiar situations will be of benefit for the preparation of an effective EMS response for HAZMAT.
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Affiliation(s)
- T M Moles
- Department of Oral and Maxillofacial Surgery, Prince Philip Hospital, Hong Kong SAR, People's Republic of China
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Green JJ, Baker DJ. Linear childhood discoid lupus erythematosus following the lines of Blaschko: a case report with review of the linear manifestations of lupus erythematosus. Pediatr Dermatol 1999; 16:128-33. [PMID: 10337677 DOI: 10.1046/j.1525-1470.1999.00030.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [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] [Indexed: 11/20/2022]
Abstract
Seventeen cases of childhood discoid lupus erythematosus (DLE) have been previously reported in the literature. We describe the first reported case of childhood linear DLE following the lines of Blaschko. The clinical and histologic characteristics of childhood DLE are discussed and a review of the linear manifestations of childhood LE is presented.
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Affiliation(s)
- J J Green
- UMDNJ-Robert Wood Johnson Medical School at Camden, New Jersey, USA
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32
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Adcock KF, Baker DJ, Padilla R. Initiating a chaplaincy program for a hospital police department. J Healthc Prot Manage 1999; 14:113-6. [PMID: 10182053] [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] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The authors discuss the creation of a police chaplain program at their hospital--why it was needed, the preparations that were necessary, the recruitment process, and the important role the police chaplain plays.
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Affiliation(s)
- K F Adcock
- Tarrant County Hospital District Police Department, Fort Worth, TX, USA
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Abstract
Here we report a method of immobilising the chaperonins GroEL and GroES to a glass matrix. The immobilised chaperone system has been used to successfully refold target proteins denatured by guanidine hydrochloride and produce substantially higher levels of active protein than occur on dilution into aqueous solution alone. The chaperone system has been shown to refold proteins from each of the three categories of GroEL substrate. The refolding of the enzyme glycerol dehydrogenase from Bacillus stearothermophilus shows a two-fold increase in activity in the presence of immobilised GroEL compared to that in free solution. The lactate dehydrogenase from B. stearothermophilus also shows a two-fold higher yield of activity in the presence of the immobilised GroEL and ATP. The presence of immobilised GroEL in the absence of ATP arrests the refolding of LDH. The enzyme citrate synthetase from porcine heart demonstrates a three-fold increase in activity when refolded in the presence of immobilised GroEL, ATP and free GroES. Similar results are obtained in the presence of free GroEL, immobilised GroES and ATP. The matrix-bound chaperone can be removed from the refolding mixture by centrifugation, producing a reusable system that can be easily isolated and purified from the refolded substrate.
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Affiliation(s)
- N S Preston
- Division of Biochemistry, Institute of Biomolecular Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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Armour EAG, Baker DJ. The theoretical treatment of low-energy e+-H2scattering using Kohn trial functions containing Hylleraas-type functions. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0022-3700/20/22/020] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Leary ET, Wang T, Baker DJ, Cilla DD, Zhong J, Warnick GR, Nakajima K, Havel RJ. Evaluation of an immunoseparation method for quantitative measurement of remnant-like particle-cholesterol in serum and plasma. Clin Chem 1998; 44:2490-8. [PMID: 9836716] [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: 02/09/2023]
Abstract
Substantial evidence indicates that triglyceride-rich lipoprotein remnants are atherogenic. Additional research has, however, been limited by available methods for separation and quantification of remnants. We have evaluated an immunoseparation assay developed to measure cholesterol in remnant-like particles (RLP-C). This method uses monoclonal antibodies to human apolipoproteins B-100 and A-I to remove most of the apolipoprotein B-100-containing lipoproteins (namely LDL and nascent VLDL) and apolipoprotein A-I-containing lipoproteins (namely chylomicrons and HDL), leaving behind a fraction of triglyceride-rich lipoproteins, including chylomicron and VLDL remnants, both of which are enriched in apolipoprotein E. Cholesterol in the unbound fraction is measured with a sensitive enzymatic assay. The RLP-C concentration was highly correlated with total triglyceride-rich lipoproteins (sum of VLDL-cholesterol and IDL-cholesterol) separated by ultracentrifugation and by polyacrylamide gel electrophoresis (r = 0.86 and 0.76, respectively). The within-run and run-to-run imprecision (CV) of the assay was approximately 6% and 10%, respectively. The assay was not affected by hemoglobin up to 5000 mg/L (500 mg/dL), bilirubin up to 342 mmol/L (20 mg/dL), glucose up to 67 mmol/L (1200 mg/dL), or ascorbic acid up to 170 mmol/L (3.0 mg/dL). In 726 subjects (men, n = 364; women, n = 362) in the US, the 75th percentiles of RLP-C concentration were 0.17 mmol/L (6.6 mg/dL) and 0.23 mmol/L (8.8 mg/dL) in sera obtained after overnight fasting or randomly, respectively. A group of 151 patients from nine US centers and one Canadian center with coronary artery atherosclerosis established by angiography had higher median RLP-C concentrations than 302 gender- and age-matched controls (P <0.05). We conclude that the RLP-C assay compares favorably to ultracentrifugation and electrophoresis and provides a convenient and economical approach to measure triglyceride-rich lipoprotein remnants in routine clinical laboratories.
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Affiliation(s)
- E T Leary
- 1 Pacific Biometrics, Inc., 220 West Harrison Street, Seattle, WA 98119, USA.
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Abstract
Shaken Baby Syndrome is a complex disorder with implications for family members (especially the victim's mother) that are felt long after the emergency diagnosis and treatment of the child are concluded. The authors conducted a Women's Support Group for parolees over a two year period. Included in its group membership were several women who had been jailed for child abuse related crimes. This article synthesizes the significant progress in the research from the medical, legal, social, nursing, and preventive health perspectives on Shaken Baby Syndrome. A case study is used to illustrate the phenomenon of victimization of the mother, typically the nonoffending parent in Shaken Baby Syndrome. The difficulties of diagnosing Shaken Baby Syndrome in a timely manner are presented with emphasis on the diagnostic ambiguities confronting the various medical and nursing providers and nonoffending perpetrators. The case study attempts to raise the consciousness of nurses, with whom the nonoffending parents come into contact in the vast array of health service settings, as well as provide specific recommendations for enhancing community health nursing practice.
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Affiliation(s)
- M I D'Lugoff
- Johns Hopkins University School of Nursing, Baltimore, Maryland, USA.
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Baker DJ, Gore MG. A chaperonin apical domain from the thermophilic bacterium Thermus Aquaticus. Biochem Soc Trans 1998; 26:S250. [PMID: 9765969 DOI: 10.1042/bst026s250] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- D J Baker
- Division of Biochemistry and Molecular Biology, School of Biological Sciences, University of Southampton, United Kingdom
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Abstract
The effectiveness of video-based staff training with manager-led exercises in improving staff performance in residential support for persons with disabilities was examined. Research staff assisted two residential program managers to implement staff training in health and safety, basic support, and residential support values. Results showed improvement in (a) staff members' washing hands when appropriate, (b) wearing gloves when appropriate, and (c) frequency of positive interactions with residents. These changes in staff behavior maintained over a 6-month follow-up. Following the values training, in one house, brief increases were observed in frequency of residents' community activities. These changes did not maintain. No improvements in these measures were noted in the other house. Implications of these findings for assurance of competent staff performance with residents were discussed.
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Affiliation(s)
- D J Baker
- University of Oregon, Eugene 97403-1235, USA.
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Cazalaà JB, Baker DJ. Design flaw in continuous syringe pumps. Intensive Care Med 1998; 24:646-7. [PMID: 9681798 DOI: 10.1007/bf03035550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kho MR, Baker DJ, Laayoun A, Smith SS. Stalling of human DNA (cytosine-5) methyltransferase at single-strand conformers from a site of dynamic mutation. J Mol Biol 1998; 275:67-79. [PMID: 9451440 DOI: 10.1006/jmbi.1997.1430] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [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: 02/06/2023]
Abstract
Single-strand conformers (SSCs) from the C-rich strand of the triplet repeat at the FMR-1 locus are rapidly and selectively methylated by the human DNA (cytosine-5) methyltransferase. The apparent affinity of the enzyme for the FMR-1 SSC is about tenfold higher than it is for a control Watson-Crick paired duplex. The de novo methylation rate for the SSC is over 150-fold higher than the de novo rate for the control duplex. Methylation of what is generally called a hemi-methylated duplex occurs with a rate enhancement of over 100-fold, while methylation of what can be viewed as a hemi-methylated FMR-1 SSC is actually slower than the de novo rate. The pronounced inhibition of the methyltransferase by the methylated SSC suggests that the enzyme has a higher affinity for the methylated product of its reaction with the SSC than it has for the unmethylated SSC substrate. Gel retardation studies show that the methyltransferase binds selectively to SSCs from the C-rich strand of the FMR-1 triplet repeat. This suggests a two-step stalling process in which the human methyltransferase first selectively methlyates and subsequently stalls at the C-rich strand SSC. Stalling may reflect the inability of the enzyme to release a DNA product that is fixed in a conformation resembling its transition state by the unusual structure of the substrate. In particular, the data suggest that DNA methyltransferase may physically participate in biological processes that lead to dynamic mutation at FMR-1. In general, the data raise the possibility that a two-step stalling process occurs at secondary structures associated with chromosome instability, chromosome remodelling, viral replication or viral integration and may account for the local hypermethylation and global hypomethylation associated with viral and non-viral tumorigenesis.
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Affiliation(s)
- M R Kho
- Department of Cell and Tumor Biology, City of Hope National Medical Center, Duarte, CA 91010-300, USA
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Abstract
This study was designed to compare the growth of Pakistani schoolchildren in the UK with the 1990 UK growth standards. Measurements of height, weight, and sitting height were performed on 785 Pakistani schoolchildren aged 5-14 years with the mean values for each age and sex being plotted on the UK growth standards. The results were expressed as SD scores relative to the 1990 reference data. The mean height for the boys was only 0.2 SD scores below the mean for the new growth standards with the mean height for the girls being 0.4 SD scores below the mean. The mean values for weight and body mass index were 0.3 and 0.5 SD scores less than the mean for boys and girls respectively. This study demonstrates that the growth of Pakistani schoolchildren in the UK is comparable to the 1990 UK growth standards with only minor differences. It is not safe to assume that short stature or low body weight in a Pakistani child is due to his or her ethnic background.
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Baker DJ, Fraser GG, Tilyard M, Gurr E. Serology testing for measles: a survey of general practitioners in Southland and Otago. N Z Med J 1997; 110:379-80. [PMID: 9364186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- D J Baker
- Student Health Service, University of Otago, Dunedin
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Baker DJ, Paterson MA. Reproductive laboratory technology: an alternative career. Clin Lab Sci 1997; 10:258-64. [PMID: 10177202] [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] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
OBJECTIVES Define the job description for reproductive laboratory technologist (RLT); describe the RLT laboratory setting; identify education level and certification of the respondents; establish level of job satisfaction and job security; determine if certification and position affect performance and job satisfaction; compare RLT job with any previous clinical laboratory position; and document education and training important for the position. SURVEY INSTRUMENT A questionnaire was developed with questions targeted to answer objectives. SURVEY POPULATION: The questionnaire was mailed to a random sample of 300 non-physician members from the Reproductive Biology Professional Group and the Reproductive Laboratory Technology Group from membership lists provided by the American Society for Reproductive Medicine. STUDY POPULATION 81 survey respondents. RESULTS RLTs are mostly college-educated, certified and non-certified laboratory professionals, trained on the job for specialty work in andrology and assisted reproductive technology (ART). Position, but not certification, correlate with job performance and job satisfaction. Respondents describe the position of RLT as stressful, but very interesting, exciting, fulfilling, and secure. Respondents with previous clinical laboratory experience rated level of job satisfaction higher for the reproductive laboratory. The CLS curriculum is an excellent background for RLT. CONCLUSIONS RLT is an exciting career alternative for CLSs. Newly formed laws and regulations, and the demand for more stringent regulation, will continue to increase the demand for certified CLSs for this position. Formal education and certification requirements are anticipated for RLT. The specialty is being incorporated in CLS training programs.
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Affiliation(s)
- D J Baker
- Department of Clinical Sciences, University of Kentucky, Lexington 40536-0003, USA.
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Temple WA, Beasley DM, Baker DJ. Nitrous oxide abuse from whipped cream dispenser chargers. N Z Med J 1997; 110:322-3. [PMID: 9315037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Abstract
We describe evidence for a sequence of events in which the Human DNA(cytosine-5)methyl-transferase first methylates spontaneous single-stranded conformers (SSCs) and then stalls at the methylated site to produce a complex with the conformationally unusual DNA. This property of the enzyme is a result of its ability to respond to a general loss of symmetry at its CG recognition site. The data suggest that DNA methyltransferase, itself, may physically participate in biological processes that distinguish between DNA that is in the normal Watson-Crick paired conformation and DNA that is conformationally unusual (e.g. a hairpin loop or misassembled replication intermediate). The in vitro methylation of spontaneous SSCs from the Huntington's locus illustrates the phenomenon.
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Affiliation(s)
- S S Smith
- Department of Cell and Tumor Biology, City of Hope National Medical Center, Duarte, California 91010-3000, USA
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Affiliation(s)
- D J Baker
- University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School at Camden, 08103, USA
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Abstract
A system for addressing in the construction of macromolecular assemblies can be based on the biospecificity of DNA (cytosine-5) methyltransferases and the capacity of these enzymes to form abortive covalent complexes at targeted 5-fluorocytosine residues in DNA. Using this system, macromolecular assemblies have been created using two representative methyltransferases: M-HhaI and M x MspI. When 5-fluorocytosine (F) is placed at the targeted cytosine in each recognition sequence in a synthetic oligodeoxynucleotide (GFGC for M x HhaI or FCGG for M x MspI), we show that the first recognition sequence becomes an address for M x HhaI, while the second sequence becomes an address for M x MspI. A chimeric enzyme containing a dodecapeptide antigen linked to the C terminus of M-HhaI retained its recognition specificity. That specificity served to address the linked peptide to the GFGC recognition site in DNA. With this assembly system components can be placed in a preselected order on the DNA helix. Axial spacing for adjacent addresses can be guided by the observed kinetic footprint of each methyltransferase. Axial rotation of the addressable protein can be guided by the screw axis of the DNA helix. The system has significant potential in the general construction of macromolecular assemblies. We anticipate that these assemblies will be useful in the construction of regular protein arrays for structural analysis, in the construction of protein-DNA systems as models of chromatin and the synaptonemal complex, and in the construction of macromolecular devices.
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Affiliation(s)
- S S Smith
- Department of Cell and Tumor Biology, City of Hope National Medical Center, Duarte, CA 91010, USA
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50
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Abstract
The need to consider the problem of acute toxic injury in the prehospital context emphasized by the recent use of highly toxic agents of warfare in terrorist attacks. Toxic agents differ widely in their nature but may be considered to have four distinct properties: toxicity, latency, persistency and transmissibility. Toxicity and latency determine the onset and pathophysiology of the poisoning and therefore the clinical management. Persistency and transmissibility determine the level of hazard to rescue personnel and the evacuation system and therefore the rationale of logistic management. Previously, special emphasis has been given to the importance of isolation and decontamination of the patient before any medical intervention can occur. This approach, however, although essential for the safety of medical responders may not be in the best interests of the patient who may be in a life-threatening situation within a contaminated zone (CONZONE). Toxic injury may require more rapid help than traumatic injury; moreover, traumatic and toxic injury may co-exist, as in the case of explosion with toxic emission. The special skills required are defined in the TOXALS programme and must now become a standard part of the training and practice of prehospital care medical care.
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Affiliation(s)
- D J Baker
- Toxic Trauma and HAZMAT Committee, International Trauma Anesthesia and Critical Care Society, Baltimore, MD, USA
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