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Jawin ER, Campbell BA, Whitten JL, Morgan GA. The Lateral Continuity and Vertical Arrangement of Dust Layers in the Martian North Polar Cap From SHARAD Multiband Data. Geophys Res Lett 2022; 49:e2022GL099896. [PMID: 36245892 PMCID: PMC9542121 DOI: 10.1029/2022gl099896] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/15/2022] [Accepted: 08/19/2022] [Indexed: 06/16/2023]
Abstract
Interpretation of radar sounder reflections to infer the structure and composition of the martian polar caps depends on whether bright returns correspond to single packed dust layers or a more finely layered structure. Reflections from multiple layers can create strong resonant scattering (interference) effects that impact analyses of radargram reflectors and inference of dielectric contrast. We identify resonant behavior for an areally extensive reflector in the north polar layered deposits from Shallow Radar data processed in two frequency bands. Echo strength varies by ∼2 dB between subband reflections across a region ∼400 km in extent, with the stronger echo shifting abruptly from the high- to low-frequency band outside the central region of Gemina Lingula. This behavior can arise from resonant scattering between two layers of dust (0.3-0.6 m thick) separated by 0.5-3 m of ice. Such layering requires there be little postdepositional aeolian activity to preserve layer thickness and spacing.
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Affiliation(s)
- Erica R. Jawin
- Smithsonian InstitutionNational Air and Space MuseumWashingtonDCUSA
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Campbell BA, Morgan GA, Whitten JL, Carter LM, Glaze LS, Campbell DB. Pyroclastic Flow Deposits on Venus as Indicators of Renewed Magmatic Activity. J Geophys Res Planets 2017; Volume 122:1580-1596. [PMID: 31709132 PMCID: PMC6839737 DOI: 10.1002/2017je005299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Radar-bright deposits on Venus that have diffuse margins suggest eruptions that distribute debris over large areas due to ground-hugging flows from plume collapse. We examine deposits in Eastern Eistla, Western Eistla, Phoebe, and Dione Regiones using Magellan data and Earth-based radar maps. The radar-bright units have no marginal lobes or other features consistent with viscous flow. Their morphology, radar echo strength, polarization properties, and microwave emissivity are consistent with mantling deposits comprised of few-cm or larger clasts. This debris traveled downhill up to ~100 km on modest slopes, and blanketed lava flows and tectonic features to depths of tens of cm to a few meters over areas up to 40×103 km2. There is evidence for ongoing removal and exhumation of previously buried terrain. A newly identified occurrence is associated with a ridge belt south of Ushas Mons. We also note radar-bright streaks of coarse material west of Rona Chasma that reflect the last traces of a deposit mobilized by winds from the formation of Mirabeau crater. If the radar-bright units originate by collapse of eruption columns, with coarse fragmental material entrained and fluidized by hot gases, then their extent suggests large erupted volatile (CO2 or H2O) amounts. We propose that these deposits reflect the early stage of renewed magmatic activity, with volatile-rich, disrupted magma escaping through vents in fractured regions of the upper crust. Rapidly eroding under Venus surface conditions, or buried by subsequent eruptions, these markers of recently renewed activity have disappeared from older regions.
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Affiliation(s)
- Bruce A. Campbell
- Center for Earth and Planetary Studies, Smithsonian Institution, MRC 315, PO Box 37012, Washington, DC 20013-7012, Phone: (202) 633-2472
| | - Gareth A. Morgan
- Center for Earth and Planetary Studies, Smithsonian Institution, MRC 315, PO Box 37012, Washington, DC 20013-7012, Phone: (202) 633-2472
| | - Jennifer L. Whitten
- Center for Earth and Planetary Studies, Smithsonian Institution, MRC 315, PO Box 37012, Washington, DC 20013-7012, Phone: (202) 633-2472
| | - Lynn M. Carter
- Lunar and Planetary Laboratory, 1629 E University Blvd., University of Arizona, Tucson, AZ 85721-0092
| | - Lori S. Glaze
- NASA Goddard Space Flight Center, Code 690, Greenbelt, MD 20771
| | - Donald B. Campbell
- Cornell University, Dept. of Astronomy, 502 Space Sciences Bldng., Ithaca, NY 14853
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Abstract
Outflow channels on Mars are interpreted as the product of gigantic floods due to the catastrophic eruption of groundwater that may also have initiated episodes of climate change. Marte Vallis, the largest of the young martian outflow channels (<500 million years old), is embayed by lava flows that hinder detailed studies and comparisons with older channel systems. Understanding Marte Vallis is essential to our assessment of recent Mars hydrologic activity during a period otherwise considered to be cold and dry. Using data from the Shallow Radar sounder on the Mars Reconnaissance Orbiter, we present a three-dimensional (3D) reconstruction of buried channels on Mars and provide estimates of paleohydrologic parameters. Our work shows that Cerberus Fossae provided the waters that carved Marte Vallis, and it extended an additional 180 kilometers to the east before the emplacement of the younger lava flows. We identified two stages of channel incision and determined that channel depths were more than twice those of previous estimates.
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Affiliation(s)
- Gareth A Morgan
- Center for Earth and Planetary Studies, Smithsonian Institution, Washington, DC, USA.
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Hennan JK, Morgan GA, Swillo RE, Antrilli TM, Mugford C, Vlasuk GP, Gardell SJ, Crandall DL. Effect of tiplaxtinin (PAI-039), an orally bioavailable PAI-1 antagonist, in a rat model of thrombosis. J Thromb Haemost 2008; 6:1558-64. [PMID: 18624980 DOI: 10.1111/j.1538-7836.2008.03063.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To assess the antithrombotic and profibrinolytic effects of tiplaxtinin (PAI-039), an orally bioavailable antagonist of PAI-1, in rat models of thrombosis. METHODS AND RESULTS Carotid artery and vena cava vascular injury was produced by application of FeCl3 and blood flow was monitored using ultrasonic technology. To assess efficacy in a thrombosis prevention paradigm, PAI-039 was administered orally 90 min before injury (1-30 mg kg(-1)). To assess efficacy in a thrombosis treatment paradigm, vascular injury and stable thrombus formation were followed 4 h later by recovery and PAI-039 administration. PAI-039 prevented carotid artery occlusion in 20, 68 and 60% of animals pretreated with 0.3, 1.0 and 3.0 mg kg(-1), respectively. Time to occlusive thrombosis was increased from 18.2 +/- 4.6 min in controls to 32.5 +/- 8.7 (P = ns), 46.1 +/- 7.0 (P < 0.05), and 41.6 +/- 11.3 min (P < 0.05) in the respective PAI-039 treatment groups. In the vena cava protocol, PAI-039 pretreatment significantly reduced thrombus weight at PAI-039 doses of 3, 10 and 30 mg kg(-1). When PAI-039 was dosed in a treatment paradigm 4 h after stable arterial and venous thrombosis, a significant reduction in thrombus weight was observed 24 h later at PAI-039 doses of 3, 10 and 30 mg kg(-1). PAI-039 (10, 30 and 100 mg kg(-1)) had no effect on platelet aggregation in response to ADP or collagen and was not associated with increased bleeding or prolonged prothrombin time. In animals bearing no vascular injury, PAI-039 had no effect on circulating, low-levels of PAI-1 activity. In contrast, circulating PAI-1 activity increased 5-fold following the induction of vascular injury, which was completely neutralized by PAI-039. CONCLUSIONS PAI-039 exerts antithrombotic efficacy in rat models of arterial and venous vascular injury without effecting platelet aggregation.
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Affiliation(s)
- J K Hennan
- Cardiovascular and Metabolic Disease Research, Wyeth Research, Collegeville, PA 19426, USA.
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Morgan GA, Harmon RJ, Gliner JA. Ethical problems and principles in human research. J Am Acad Child Adolesc Psychiatry 2001; 40:1231-3. [PMID: 11589537 DOI: 10.1097/00004583-200110000-00018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Abstract
We have provided an overview of techniques used to assess variables in the applied behavioral sciences. Most of the methods are used by both quantitative/positivist and qualitative/constructivist researchers but to different extents. Qualitative researchers prefer more open-ended, less structured data collection techniques than do quantitative researchers. Direct observation of participants is common in experimental and qualitative research; it is less common in so-called survey research, which tends to use self-report questionnaires. It is important that investigators use instruments that are reliable and valid for the population and purpose for which they will be used. Standardized instruments have manuals that provide norms and indexes of reliability and validity. However, if the populations and purpose on which these data are based are different from yours, it may be necessary for you to develop your own instrument or provide new evidence of reliability and validity.
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Affiliation(s)
- G A Morgan
- Education and Human Development, Colorado State University, Fort Collins, USA
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- J A Gliner
- Occupational Therapy and Education, Colorado State University, Fort Collins, USA
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Affiliation(s)
- J A Gliner
- Occupational Therapy and Education, Colorado State University, Fort Collin, USA
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Affiliation(s)
- J A Gliner
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- J A Gliner
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Morgan GA, Gliner JA, Harmon RJ. Measurement and descriptive statistics. J Am Acad Child Adolesc Psychiatry 1999; 38:1313-5. [PMID: 10517066 DOI: 10.1097/00004583-199910000-00022] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Crandall DL, Quinet EM, Morgan GA, Busler DE, McHendry-Rinde B, Kral JG. Synthesis and secretion of plasminogen activator inhibitor-1 by human preadipocytes. J Clin Endocrinol Metab 1999; 84:3222-7. [PMID: 10487691 DOI: 10.1210/jcem.84.9.5987] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [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: 11/19/2022]
Abstract
To further investigate the role of plasminogen activator inhibitor-1 (PAI-1) in adipose tissue physiology, the production and regulation of PAI-1 was determined in primary cultures of human preadipocytes. When expressed as production per cell and cultured under identical conditions, human preadipocytes from both visceral (omental) and sc depots of lean and obese individuals released significant, yet similar, amounts of PAI-1 protein into the conditioned medium. High steady-state PAI-1 messenger RNA (mRNA) concentrations were observed in visceral and sc preadipocytes, with the relative level of expression equivalent to beta-actin mRNA. Tumor necrosis factor alpha significantly decreased PAI-1 production in a concentration-dependent manner in both visceral and sc cultures, whereas transforming growth factor beta significantly elevated PAI-1 production, but only in sc preadipocytes from obese individuals. Addition of insulin had no effect on antigen levels in conditioned medium of preadipocyte cultures. Stimulation of the preadipocyte cultures with a defined medium resulted in differentiation to the adipocyte phenotype, as determined by flow cytometric analysis, verifying the cultures as human preadipocyte. These studies are the first to observe significant PAI-1 mRNA expression and protein production in primary cultures of a human adipose tissue cellular component, and they suggest that nascent adipocytes contribute significantly to the elevated plasma PAI-1 observed in obesity.
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Affiliation(s)
- D L Crandall
- Wyeth-Ayerst Laboratories, Inc. Research, Radnor, Pennsylvania 19101, USA.
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- R J Harmon
- Division of Child Psychiatry, University of Colorado School of Medicine, Denver, USA
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Affiliation(s)
- G A Morgan
- Colorado State University, Fort Collins, USA
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Gliner JA, Morgan GA, Harmon RJ. A tale of two paradigms. J Am Acad Child Adolesc Psychiatry 1999; 38:342-3. [PMID: 10087698 DOI: 10.1097/00004583-199903000-00024] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- J A Gliner
- Colorado State University, Fort Collins, USA
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Affiliation(s)
- G A Morgan
- Education and Human Development, Colorado State University, Fort Collins, USA
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Harmon RJ, Morgan GA. Clinicians' guide to research methods and statistics: series preface. J Am Acad Child Adolesc Psychiatry 1999; 38:99-100. [PMID: 9893423 DOI: 10.1097/00004583-199901000-00026] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- R J Harmon
- Division of Child Psychiatry, University of Colorado School of Medicine, Denver, USA
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Petros A, Schindler M, Pierce C, Jacobe S, Mok Q, Nel MR, Nadel S, Marriage S, De Munter C, Britto J, Habibi P, Levin M, Kaag M, Zoetmulder FAN, Riordan FAI, Williams A, Thomson APJ, Soni N, Goodman NW, Beale RJ, Wyncoll DLA, McLuckie A, Frame JD, Moiemem N, Chalmers I, Lawler PG, Morgan GA, Shwe KH, Bhavnani M, Roberts I. Human albumin administration in critically ill patients. BMJ 1998. [DOI: 10.1136/bmj.317.7162.882] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Lawler PG, Morgan GA. Human albumin administration in critically ill patients. Modified editorial might have restrained media response. BMJ 1998; 317:885. [PMID: 9786702] [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: 02/09/2023]
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Abstract
A 41-year-old woman was admitted to the Intensive Care Unit with a severe exacerbation of asthma. She was exhausted despite maximal standard medical treatment. Instead of tracheal intubation and mechanical ventilation a subanaesthetic dose of halothane was delivered in 100% oxygen using a close-fitting face mask. Her bronchospasm resolved within minutes. The argument for using inhaled halothane to avoid tracheal intubation, mechanical ventilation and their side-effects is presented.
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Affiliation(s)
- A J Padkin
- Department of Anaesthesia and Intensive Care, Royal Cornwall Hospital, Treliske, Truro, UK
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Abstract
Trypanosoma brucei S 427 clone 1 accumulated in G1 when incubated under growth-limiting conditions. Further incubation of the G1-restricted organisms in medium containing 10% fetal bovine serum (FBS) and 2 mM hydroxyurea resulted in their reversible arrest after a G1 checkpoint beyond which serum was not required for progress into and through S. Progress of the G1-restricted T. brucei through the G1 checkpoint was linear and required continuous incubation with exogenous serum growth factors. These were principally low and high density lipoproteins; both lipoproteins triggered G1 progression in a dose- and time-dependent manner whilst their removal by immunoaffinity chromatography severely reduced the capacity of FBS to stimulate G1 progression. Serum-induced progress of T. brucei through G1 was Ca(2+)-independent, but required gene transcription, protein synthesis, and continuous kinase activity that was inhibited by tyrphostin 51 and DAPH 1 which typically inhibit epidermal growth factor receptor protein tyrosine kinase activity. The tyrphostin 51-sensitive catalytic activity was not required for T. brucei protein synthesis, glycolysis, or S phase progression but was required for tyrosine phosphorylation of several polypeptides, none of which was specifically associated with serum-induced G1 progression.
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Affiliation(s)
- G A Morgan
- Department of Microbiology, Ohio State University, Columbus 43210, USA
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Reduth D, Grootenhuis JG, Olubayo RO, Muranjan M, Otieno-Omondi FP, Morgan GA, Brun R, Williams DJ, Black SJ. African buffalo serum contains novel trypanocidal protein. J Eukaryot Microbiol 1994; 41:95-103. [PMID: 8167620 DOI: 10.1111/j.1550-7408.1994.tb01480.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The high ability of African buffalo, as compared to domestic cattle, to control infections with Trypanosoma brucei brucei ILTat 1.4 organisms did not correlate with the timing or magnitude of parasite surface coat-specific antibody responses and may have resulted from the constitutive presence in buffalo blood of a novel trypanocidal factor. Buffalo plasma and serum contained material that killed bloodstream stage T. b. brucei, T. b. rhodesiense, T. b. gambiense, T. evansi, T. congolense, and T. vivax organisms during four h of incubation at 37 degrees C in vitro. Serum from eland was also trypanocidal whereas serum from oryx, waterbuck, yellow-back duiker, cattle, horse, sheep, goat, mouse, rat, and rabbit was not trypanocidal. The buffalo serum trypanocidal material was not lipoprotein, or IgG, and had the following properties: 1) a density of > 1.24 g/ml determined by flotation ultracentrifugation; 2) insolubility in 50% saturated ammonium sulphate; 3) non-reactivity with anti-bovine IgM, and anti-bovine IgG; 4) non-reactivity with protein G, and protein A; 5) a relative molecular mass of 152 kDa determined by chromatography on Sephacryl S 300, and of 133 kDa determined by chromatography of the 50% SAS cut of IgG-depleted buffalo serum on Superose 12; 6) no associated cholesterol; and 7) inactivation by digestion with proteinase K that was immobilized on agarose.
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Morgan GA, Laufman HB, Otieno-Omondi FP, Black SJ. Control of G1 to S cell cycle progression of Trypanosoma brucei S427cl1 organisms under axenic conditions. Mol Biochem Parasitol 1993; 57:241-52. [PMID: 8433715 DOI: 10.1016/0166-6851(93)90200-h] [Citation(s) in RCA: 16] [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: 01/30/2023]
Abstract
Trypanosoma brucei S427cl1 organisms made 6 divisions in modified minimal essential medium (BMEM) supplemented with fetal bovine serum (FBS)-low or high density lipoprotein (LDL, HDL) and fatty acid-free bovine serum albumin (FAF-BSA). Omission of lipoproteins or FAF-BSA from the medium caused the parasites to accumulate in G1 of the cell cycle and to lose the ability to replicate at 37 degrees C. Proteinase K-treated LDL or HDL, which did not have detectable apolipoprotein, supported the G1 to S cell cycle transition of T. brucei S427cl1 organisms in BMEM supplemented with FAF-BSA. Addition of C6:0, C7:0 or fatty C8:0 fatty acid (1 mol fatty acid mol-1 FAF-BSA in the incubation mixture) to serum-free medium supplemented with LDL or HDL and FAF-BSA prevented T. brucei S427cl1 organisms from progressing through G1 into S of the cell cycle. T. brucei S427cl1 organisms became stumpy-like forms during plateau phase growth under axenic conditions. Stumpy-like T. brucei S427cl1 organisms were mainly in G1 of the cell cycle, expressed raised levels of NAD diaphorase activity, were unable to replicate at 37 degrees C, but were able to differentiate to replicating procyclic organisms. Medium collected from plateau phase cultures of T. brucei S427cl1 did not support the G1 to S cell cycle transition of exponentially growing T. brucei organisms. The capacity of plateau phase medium to support G1 to S transition of T. brucei S427cl1 organisms was restored by addition of FAF-BSA and its capacity to support 4 cycles of replication of the parasites was restored by addition of FAF-BSA and LDL or HDL.
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Affiliation(s)
- G A Morgan
- Department of Microbiology, Ohio State University, Columbus 43210-1292
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Affiliation(s)
- M D Finch
- Intensive Care Unit, Royal Cornwall Hospital (Treliske), Truro
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Abstract
Some remarkable cases of full neurological recovery after cardiac arrest following immersion incidents have been intermittently reported in the journals over the years. These have largely been in children or teenagers who have fallen into extremely cold water. We report here two older adults who recovered completely after a period of cardiac arrest in cold water. Certainly, death should not be pronounced in cold water drowning, without a thermometer reading and ECG.
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Affiliation(s)
- N D Edwards
- Anaesthetic Department, Treliske Hospital, Truro, Cornwall, UK
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Edwards N, Morgan GA. How to insert a central venous catheter. Br J Hosp Med (Lond) 1989; 42:312, 314-5. [PMID: 2804503] [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: 01/02/2023]
Abstract
Familiarity with the anatomy of the central veins, the equipment to be used and attention to technical detail are fundamental to successful and rapid central venous cannulation. This article provides a concise description of the relevant anatomy, some general advice and a brief account of the common methods of cannulation. Emphasis has been placed on practical detail and commonly encountered pitfalls.
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Affiliation(s)
- N Edwards
- Intensive Care Unit, Royal Cornwall Hospital, Treliske, Truro
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Abstract
A case of argyria secondary to the prolonged use of nasal drops that contained mild silver protein is presented. The patient was thought to be cyanosed immediately after a total knee replacement. Argyria, its differentiation from cyanosis and its prevention are discussed. The need for a careful drug history is noted.
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Affiliation(s)
- A C Timmins
- Intensive Care Unit, Royal Cornwall Hospital (Treliske), Truro, Cornwall
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Landfield PW, Morgan GA. Chronically elevating plasma Mg2+ improves hippocampal frequency potentiation and reversal learning in aged and young rats. Brain Res 1984; 322:167-71. [PMID: 6097334 DOI: 10.1016/0006-8993(84)91199-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
One prediction of the hypothesis that the capacity for hippocampal frequency potentiation is relevant to behavioral plasticity is tested in this study, by chronically elevating magnesium in intact aged and young rats. Elevated extracellular Mg2+ specifically improves frequency potentiation in hippocampal slices, and chronic alterations in plasma Mg2+ can increase brain Mg2+ in intact animals. Aged and young rats on a diet that elevated plasma Mg2+ exhibited stronger frequency potentiation under urethane anesthesia, and showed improved maze reversal learning.
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Aycock EK, Morgan GA, Birch WE. Giardiasis Tuscaloosa County. Ala Med 1984; 53:16-8, 20, 25. [PMID: 6731208] [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: 01/21/2023]
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Abstract
This paper reviews research on the issue of continuities and discontinuities in development, focusing on affective and cognitive-motivational aspects. The theoretical view of Rene Spitz and supporting research is reviewed related to transformations in affective development. Methods of assessment of cognitive-motivational development ("mastery motivation") are described as utilized in a number of studies. These studies illustrate developmental transformations at approximately 10 and 18 months of age in normal infants. In addition, findings comparing abused/neglected and perinatal risk infant populations with normal infants illustrate differences in both affective and cognitive-motivational development.
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Gaiter JL, Morgan GA, Jennings KD, Harmon RJ, Yarrow LJ. Variety of cognitively oriented caregiver activities: relationships to cognitive and motivational functioning at one and 31/2 years of age. J Genet Psychol 1982; 141:49-56. [PMID: 7142983 DOI: 10.1080/00221325.1982.10533456] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
This study investigated relationships between the variety of infants' social experience and their cognitive competence and motivation to master the environment. A measure of the variety of cognitively-oriented social activities with regular caregivers was significantly related to the Bayley Mental Development Index at 13 months and to three of the four McCarthy Scales of Children's Abilities at 31/2 years. The relationships were especially strong with language development at both 1 and 31/2 years. Some relationships between the variety of cognitively-oriented caregiver activities and mastery motivation were found at 1, but not at 31/2 years of age. Infant experience was not related to 13-month motor development.
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Morgan GA, Steward DJ. A pre-formed paediatric orotracheal tube designed based on anatomical measurements. Can Anaesth Soc J 1982; 29:9-11. [PMID: 7055754 DOI: 10.1007/bf03007940] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
Linear airway dimensions from incisor teeth to vocal cords were measured from radiographs. Normal children were slightly taller and heavier than children being treated for cleft palate and had significantly longer upper airway dimensions. Tracheal length was measured in 50 normal children breathing spontaneously under general anaesthesia and was found to correlate best with body weight. Strong positive correlation with height was also found. Data from normal children in these two studies were used to calculate the distance from lips to mid-trachea to determine optimal length for a tracheal tube. Previously published data on airway lengths in children are reviewed.
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Harmon RJ, Morgan GA, Klein RP. Determinants of normal variation in infants' negative reactions to unfamiliar adults. J Am Acad Child Psychiatry 1977; 16:670-83. [PMID: 599235 DOI: 10.1016/s0002-7138(09)61186-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Morgan GA, Goodson FE, Jones T. Age differences in the associations between felt temperatures and color choices. Am J Psychol 1975; 88:125-30. [PMID: 1236563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Thirty-six subjects, twelve each at 6, 12, and 18 years of age, were asked which of four colors (blue, green, yellow, or red) they were reminded of by each of four temperatures (containers at 4, 23, 35, or 45 deg C). More 18-year-olds than expected by chance made each of the conventional associations: hot/red, warm/yellow, cool/green, cold/blue. The 12-year-olds reliably made the hot/red association but none of the others. No more 6-year-olds than expected by chance made any of the conventional associations. The results suggest that the conventional associations are founded on a loosely held cultural norm rather than on an evolutionary or physiological basis.
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Bischop CR, Janzen RE, Landals DC, Manns BD, McCartney DJ, Morgan GA, Pawlyshyn VP, Schienbein AJ, Scigliano BW, Taylor KL. Effects of rumen stasis on sulfamethazine blood levels after oral administration in sheep. Can Vet J 1973; 14:269-71. [PMID: 4761169 PMCID: PMC1696269] [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: 01/12/2023]
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Druck JS, Morgan GA. The endosseous blade implant: report of two cases. J Can Dent Assoc (Tor) 1973; 39:123-7. [PMID: 4510582] [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: 01/11/2023]
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48
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49
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Kimber PM, Morgan GA. Cerebral angiography by arterial catheterization. Nurs Times 1970; 66:1137-40. [PMID: 5452550] [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: 01/15/2023]
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50
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