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Biomedical subjects

G A Morgan

Publications and source records attributed to G A Morgan.

At least 37 records · Page 2Linked to original sources
PubMed1999

Synthesis and secretion of plasminogen activator inhibitor-1 by human preadipocytes.

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.

Actins↗
PubMed1997

Halothane treatment of severe asthma to avoid mechanical ventilation.

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.

Acute Disease↗
PubMed1996

The requirements for G1 checkpoint progression of Trypanosoma brucei S 427 clone 1.

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.

Animals↗
PubMed1993

Control of G1 to S cell cycle progression of Trypanosoma brucei S427cl1 organisms under axenic conditions.

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.

Animals↗
PubMed1990

Survival in adults after cardiac arrest due to drowning.

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.

Aged↗
PubMed1989

How to insert a central venous catheter.

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.

Catheterization, Central Venous↗
PubMed1988

Argyria or cyanosis.

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.

Aged↗
PubMed1984

Chronically elevating plasma Mg2+ improves hippocampal frequency potentiation and reversal learning in aged and young rats.

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.

Age Factors↗
PubMed1984

Continuities and discontinuities in affective and cognitive-motivational development.

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.

Affect↗
PubMed1982

Linear airway dimensions in children: including those from cleft palate.

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.

Adolescent↗