Search PubMed⌕ Search

Biomedical subjects

G D Phillips

Publications and source records attributed to G D Phillips.

At least 91 records · Page 5Linked to original sources
PubMed1988

Absence of a late-phase response or increase in histamine responsiveness after bronchial provocation with adenosine 5'-monophosphate in atopic and non-atopic asthma.

1. Adenosine 5'-monophosphate (AMP) causes bronchoconstriction in atopic and non-atopic asthma by a mechanism believed to involve histamine release from airway mast cells. To determine whether preformed mast cell mediators, principally histamine, can initiate a late-phase bronchoconstriction we have investigated the effect on the airways over a 24 h period of a single bronchial challenge with AMP. 2. Six atopic asthmatic subjects (all late responders to inhaled allergen) and six non-atopic asthmatic subjects were studied on two occasions for a 24 h period after inhalation of the provocation concentration of AMP required to produce a 20% fall in forced expiratory volume in 1 s (FEV1) from baseline (PC20) and 0.9% (w/v) sodium chloride placebo, respectively. The atopic asthmatic subjects were studied on a further occasion after challenge with the PC20 allergen. 3. Inhalation of the PC20 AMP resulted in an immediate fall in FEV1 to a mean maximum 25.5% below baseline without resulting in any late decrease in airway calibre. No significant increase in non-specific bronchial responsiveness as determined by measuring the PC20 histamine before, and at 3, 9 and 24 h after, AMP challenge, occurred. Inhalation of the PC20 allergen caused a reproducible late-phase bronchoconstriction and increase in non-specific bronchial responsiveness in all the atopic asthmatic subjects studied. 4. These results suggest that preformed mast cell mediators, principally histamine, play no role in the initiation of the late-phase reaction in allergen-provoked asthma, although they may contribute to the inflammatory changes involved.

Adenosine Monophosphate↗
PubMed1988

Central venous catheter stiffness and its relation to vascular perforation.

Delayed central venous perforation is an uncommon but serious complication of central venous catheter insertion. An increase in catheter stiffness may have been responsible for our association of venous perforation with use of a guidewire insertion technique. A bench model was used to investigate the stiffness characteristics of thirty-four different types of catheters. The initial stiffness is poorly described by material or catheter gauge. A large range of values is seen between apparently similar catheters--the 16 gauge polyethylene catheter associated with two perforations at our institution had an initial stiffness value 7.5 Nm2 X 10(-5) at 37 degrees C in comparison with our previous standard--the 16 gauge Deseret Intracath with an initial stiffness of 2 Nm2 X 10(-5). Multilumen catheters had a similar range of stiffness to single lumen catheters, while paediatric catheters in general were less stiff. Dialysis catheters were up to five times as stiff as the stiffest central venous catheter. Stiffness decayed at a rate and to an extent which differed from catheter to catheter. Absorption of water by the catheter appears to be one factor involved in stress relaxation.

Aged↗
PubMed1988

Dose-related antagonism of leukotriene D4-induced bronchoconstriction by p.o. administration of LY-171883 in nonasthmatic subjects.

Leukotriene D4 (LTD4) has been suggested as a proinflammatory mediator in asthma. We have investigated the inhibitory activity of the p.o. LTD4 antagonist LY-171883 (1-[2-hydroxy-3-propyl]-4-[4-(1H-tetrazol-5-yl)butoxy]phenyl]et hanone) on LTD4-induced bronchoconstriction in nonasthmatic subjects, in a double-blind, placebo controlled, randomized, cross-over study. Twelve subjects, mean age 26.3 +/- 1.7 years, participated. On 4 separate days, base-line measurements of forced expiratory volume in 1 second (FEV1) and maximum flow at 70% of vital capacity below total lung capacity (Vp30) were performed, after which subjects ingested either 50 or 200 or 400 mg of LY-171883, and then undertook a dose-response study with inhaled LTD4. Measurements of FEV1 and Vp30 were made at intervals for 8 min after inhalation of each dose of LTD4, and increasing doses administered until FEV1 had fallen by greater than 20% or the maximum cumulative dose of LTD4 (88.2 nmol) had been given. Cumulative dose-response curves were constructed on a logarithmic scale, and the provocation doses of LTD4 producing a 12% fall in FEV1 (PD12 FEV1) and a 30% fall in Vp30 (PD30Vp30) after placebo determined by linear interpolation to be 5.5 (0.9-176.4) and 1.2 (0.1-6.2) nmol, respectively. Following the 50-, 200- and 400-mg doses of LY-171883, the geometric mean PD12 FEV1 values were 7.0 (NS), 10.5 (NS) and 25.3 (P less than .01) nmol, respectively, whereas corresponding values for PD30Vp30 were 1.7 (NS), 2.6 (NS) and 6.1 (P less than .01) nmol.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetophenones↗
PubMed1987

Survival of myogenic cells in freely grafted rat rectus femoris and extensor digitorum longus muscles.

The objective of this study was to determine how long myogenic cells can survive in the central ischemic zone of early free muscle grafts in the rat. The study was conducted on free grafts of a large (rectus femoris) and a small (extensor digitorum longus) muscle. At times ranging from zero hr to five days post-grafting, the central zones were isolated, minced, and implanted under the back skin of mice. After five days the minces were removed and examined histologically for the presence of rat myotubes, which should form only in minces that contain viable myogenic cells. The results show that myogenic cells survive two to four hr in the ischemic centers of the large rectus femoris grafts; after longer post-grafting intervals, rat myotubes did not arise in central zone minces. In grafts of small muscles, myotubes consistently appeared in central zone minces. Since the formerly ischemic central areas of rectus muscle grafts are ultimately replaced by regenerating muscle fibers, we conclude that these regenerating muscle fibers are derived from precursor cells located outside of the ischemic zone.

Animals↗
PubMed1987

Effect of oral terfenadine on the bronchoconstrictor response to inhaled histamine and adenosine 5'-monophosphate in non-atopic asthma.

Inhaled adenosine 5'-monophosphate (AMP) causes bronchoconstriction in atopic asthma, probably after in vivo conversion to adenosine. It has been suggested that adenosine potentiates preformed mediator release from mast cells on the mucosal surface of the airways by interacting with specific purinoceptors, without affecting the release of newly generated mediators. The airway response of nine non-atopic subjects with "intrinsic" asthma to inhaled AMP and the influence of the oral, selective H1 histamine receptor antagonist terfenadine on this response was investigated. The geometric mean provocation concentrations of histamine and AMP required to produce a 20% fall in FEV1 (PC20) were 1.82 and 13 mmol/l. In subsequent placebo controlled time course studies the FEV1 response to a single inhalation of the PC20 histamine was ablated after pretreatment with oral terfenadine 180 mg. This dose of terfenadine caused an 80% inhibition of the bronchoconstrictor response to the PC20 AMP when measured as the area under the time course-response curve and compared with the response to PC20 AMP preceded by placebo. Terfenadine 600 mg failed to increase protection against AMP further, but both doses of terfenadine delayed the time at which the mean maximum fall in FEV1 after AMP was achieved. Terfenadine 180 mg had no effect on methacholine induced bronchoconstriction in the same subjects. These data suggest that inhaled AMP may potentiate the release of preformed mediators from preactivated mast cells in the bronchial mucosa of patients with intrinsic asthma.

Adenosine Monophosphate↗
PubMed1986

Manual resuscitators and portable ventilators.

This paper reviews the state of the art in Australia of manually operated, self-inflating bag resuscitators, including the Laerdal, Air Viva and Ambu; manually operated bags dependent upon an oxygen supply, including Mapleson B, C, E and F, the CIG Medishield Oxy-Saver and modified Oxy-Viva Resuscitator 3, and the Komesaroff Oxy-Resuscitator RD85; oxygen-powered resuscitators, including the Oxy-Viva Resuscitator 3 with Demand and RM2 Valves, and the Oxylife FM85; and portable ventilators, including the Drager Oxylog, and Ohmeda Logic 07. Specific comment is made to the effect that the design of the resuscitator is often less important than the knowledge and ability of the operator in using the equipment to achieve adequate lung ventilation. The simplest, cheapest, most useful resuscitators are the manually operated self-inflating bag assemblies. With special training, use of more complex equipment can be justified in some circumstances. The more complex the equipment, the greater the risk of inappropriate use, and the greater the risk of equipment malfunction unless a regular maintenance program is followed.

Humans↗
PubMed1985

Total parenteral nutrition in acute illness.

Successful total parenteral nutrition in acute illness requires an appreciation of the pathophysiology of the illness and an understanding of the nutritional state of the patient, as well as a knowledge of the principles of total parenteral nutrition. Management of the acutely ill patient's general condition is essential prior to the introduction of nutritional support. A basic regimen which includes administration of 1-2g/kg/day of protein, and 8,400 kJ (2,000 kcal)/day of energy, part glucose and part lipid, together with all minerals, vitamins and zinc, in an appropriate amount of water, should be provided. Modifications to this regimen may be indicated to accommodate cardiac, respiratory, liver or renal failure. The questions of the optimum mix of carbohydrate and lipid, the ideal amount of protein and the correct mix of amino acids for a particular period in an individual patient's illness, are still debated. The fact that recent research supports many of the postulates of the Scandinavian pioneers of total parenteral nutrition suggests we may be returning to a correct approach.

Acute Disease↗
PubMed1983

Nurse staffing in Intensive Care Units.

Allocation of nursing staff to patient care in our teaching hospital Intensive Care Unit is based on providing the care considered necessary, bearing in mind the experience of the nursing staff and the care requirements of the patients. A detailed study of the nurse:patient ratio over a two month period has been carried out. It was found that there was considerable variation in both hours of care required and hours of care delivered from shift to shift. The study supported the principles used in staff allocation based on professional judgement, namely the acceptance of a high nurse: patient ratio, with other staff available for special duties, administration and education.

Australia↗
PubMed1982

Computer-based monitoring and data analysis in anaesthesia and intensive care.

A computer with a software package for physiological monitoring at the bedside has been set up, modified and used in a Department of Anaesthesia and Intensive Care over the last three and a half years. Many difficulties have been experienced in implementing a useful computer-based program for monitoring physiological data. The cost of further development to overcome these difficulties could not be justified, and demands for computer time to allow storage and analysis fo other data was increasing. A decision was therefore made to eliminate the monitoring role of the computer, and it is now used for storage and analysis of administrative and clinical data from the Intensive Care Unit, Operating Theatres and Pain Management Unit.

Anesthesiology↗
PubMed1982

A clinical evaluation of safflower oil emulsion in total parenteral nutrition.

A new intravenous safflower oil emulsion (Liposyn, Abbott) was administered to 23 patients receiving total parenteral nutrition. In a prospective clinical trial, 500 ml of the 10% emulsion was administered each day for a minimum of 10 days. Plasma fatty acid estimations showed a rise in linoleic acid in 22 patients, and a fall in triene/tetraene ratio ( a guide to the presence of essential fatty acid deficiency), in 17 patients within four days of commencement of the infusion. Administration of Liposyn prevented the development of biochemical evidence of essential fatty acid deficiency. There were no clinical side effects attributable to the emulsion. Elevation of serum triglyceride and liver enzyme concentrations occurred in some patients.

Adult↗
PubMed1982

Parenteral nutrition: current status and concepts.

Parenteral nutrition is regarded as a form of nutrition in some countries and as an extension of intravenous fluid therapy in others. The optimum clinical application of parenteral nutrition as a form of therapy requires detailed knowledge of the nutrient solutions themselves, including the commonly used solutions such as dextrose, soybean oil emulsion, synthetic crystalline L-amino acid solutions; older solutions such as xylitol, protein hydrolysates; and newer solutions such as glycerides and special purpose amino acid solutions. Additionally, information has accumulated over the past 10 years, leading to the rational use of vitamins and trace elements in parenteral nutrition. Metabolism of the substrates has been correlated with known pathways of intermediary metabolism in normal, starved and stressed subjects. Several new concepts have arisen: a) Infusion of excessive quantities of dextrose results in lipogenesis and increased carbon dioxide production. Hyperalimentation of this type is being replaced by infusion of lesser quantities of dextrose, supplemented by intravenous infusion of lipid as a calorie source. b) Protein hydrolysates and racemic synthetic crystalline amino acid solutions have been replaced by synthetic crystalline L-amino acid solutions. c) A new fat emulsion based on safflower oil is competing successfully with the traditional soybean oil emulsion. d) Newer substrates are being explored. These include branched chain amino acids, keto analogues of amino acids, synthetic glycerides and maltose. e) Deficiencies of essential fatty acids, trace elements and vitamins have been studied in patients on long term parenteral nutrition and their mechanisms elucidated. Official recommendations for intravenous administration of these nutrients have been made. f) Several techniques have been applied in several circumstances, including protein sparing therapy, cyclic nutrition, home therapy, and parenteral nutrition in liver and renal failure. Parenteral nutrition is now used extensively, not only in major hospitals where the resources of a team approach with physician, nurse, pharmacist and dietitian are available, but also in smaller hospitals where all of these facilities may not be at hand. However, whatever the setting, the principles behind the clinical application of parenteral nutrition should be well understood by those involved, including current approaches to safe preparation and infusion of parenteral nutrition solutions.

Amino Acids↗
PubMed1982

Tolerance of young turkey poults to various combinations of dietary furazolidone and salt.

Three feeding trials were conducted to study the tolerance of young turkey poults to furazolidone and to various combinations of salt and furazolidone in the diet. Poults of mixed sexes tolerated up to 0.03% dietary furazolidone from hatch to six weeks of age without harmful effects as judged from the data on mortality rate, feed intake, body weight and plasma composition. High mortality with cardiac dilation and ascites occurred in poults fed the same basal diet containing 0.05 or 0.07% furazolidone. Mortality was positively related to levels of dietary furazolidone, and occurred mainly between two and four weeks of age. The cumulative feed intake and body weight of these poults were significantly lower than those of the control poults at six weeks of age. There was indication of decreased renal function in poults on high furazolidone intake and the mechanism of furazolidone-induced cardiac dilation is discussed. Mortality rate, incidence of cardiac dilation with ascites and heart, liver and body weights and feed efficiency were similar in poults fed diets containing 0.022% furazolidone and varying levels of salts (0.5, 1.0 or 1.5%) compared with the control fed the same basal diet containing 0.5% salt from hatch to eight weeks of age. It is concluded that a starter diet containing 0.022% furazolidone and up to 1.5% salt does not affect the performance of poults from hatch to eight weeks of age.

Age Factors↗
PubMed1981

Parenteral administration of trace elements to critically ill patients.

Studies of zinc, copper, manganese, chromium, selenium and molybdenum balance were carried out in eight patients in an intensive care unit. In six of these, nickel balance was also measured. The amount of each element in fluid administered to the patients, and the amount lost in urine and gastrointestinal fluid on each of seven days, was measured by atomic absorption spectrometry and cumulative balances calculated. Satisfactory balances of zinc, copper and manganese were obtained when the amounts administered approximated those currently recommended. Chromium balances were variable, while those of molybdenum, selenium and nickel were negative in most patients. Interpretation of balance studies of this type in critically ill patients is made difficult by abnormal renal and gastrointestinal function.

Adult↗
PubMed1980

First aid in disasters.

If you are first on the scene of a disaster, approach safely and liaise with police and ambulance officers. Carry out triage, identifying those victims who need urgent treatment and those who do not--because they are not ill enough, too ill or dead. Establish priorities of treatment within the urgent group in the airway (A), breathing (B), circulation (C) sequence. Record assessment and treatment given.

Adult↗