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Biomedical subjects

P Ellis

Publications and source records attributed to P Ellis.

At least 19 recordsLinked to original sources
PubMed1992

Sucrose promotes the functional activity of blood vessels after cryopreservation in DMSO-containing fetal calf serum.

The cryoprotective effect of sucrose has been investigated using 3 different vascular smooth muscle preparations, namely canine saphenous veins and arteries and porcine circumflex coronary arteries following storage in liquid nitrogen (at -196 degrees C). Contractile responses to noradrenaline, 5-HT, prostaglandin F2 alpha and KCl and relaxant responses to substance P and 5-HT were determined on fresh tissues and after cryostorage in fetal calf serum (FCS) containing either 1.8 M dimethyl sulfoxide (DMSO), or 0.1 M sucrose or both agents combined. The data demonstrate that the addition of sucrose to the DMSO-containing cryomedium promotes the preservation of both contractile and relaxant activity of cryostored blood vessels, though sucrose alone did not confer any noticeable protection.

Animals↗
PubMed1992

Neutrophils from patients undergoing hip surgery exhibit enhanced movement under spinal anaesthesia compared with general anaesthesia.

The purpose of this research was to investigate whether the effects of regional anaesthesia on neutrophil migration differ from those due to general anaesthesia during major orthopaedic surgery in human patients. Eighteen patients underwent spinal or general anaesthesia (halothane or isoflurane) for surgery (six patients in each group). Blood samples were taken prior to induction of anaesthesia and after surgery was in progress for one hour. The movement of isolated neutrophils was measured in both samples in the chemotactic chamber toward lipopolysaccharide activated pooled serum. In addition plasma concentrations of catecholamines were determined in the blood samples. Neutrophils extracted from peripheral blood during spinal anaesthesia and surgery moved further towards a complement-derived attractant than neutrophils obtained from patients undergoing surgery under general anaesthesia with halothane or isoflurane and surgery (156.4 +/- 7.6 microns vs 114.3 +/- 6.1 microns or 119 +/- 8.4 microns respectively, P < 0.05). Increased concentrations of adrenaline were present in both general anaesthetic groups whereas the spinal group had lower concentrations than those prior to anaesthesia and surgery. It is considered unlikely that these differences in neutrophil reactivity are due to the direct effects of anaesthetic agents employed. The effects are likely to be the result of differing effects of spinal anaesthesia on the stress response or immunological mediators.

Adult↗
PubMed1992

Environmentally contaminated families: therapeutic considerations.

The unique stress for families of exposure to environmental toxins is discussed in terms of the physical characteristics of such contaminants and resultant adaptational dilemmas, the agent or cause of the injury, and institutional responses to the contamination. Recommendations for mental health professionals working with contaminated families are presented.

Adaptation, Psychological↗
PubMed1991

Dimensions of the human posterior septal space and coronary sinus.

Accurate anatomic localization of accessory pathways during preoperative electrophysiologic study and during operative mapping depends on a knowledge of the dimensions of the posterior septal space and the left free wall. These dimensions were therefore studied in 48 human cadaver hearts. Mean distance from the coronary sinus orifice to the left margin of the posterior septal space was 2.3 +/- 0.4 cm and mean length of the left free wall was 5.0 +/- 1.0 cm. The posterior septal space at the level of the valve anuli extended a mean of 3.4 +/- 0.5 cm around the epicardium. The width of the posterior septum measured in the coronary sinus was related to heart weight and a combination of body weight and patient age (p less than 0.05). The probability of an accessory pathway being located in the left free wall or the posterior septum during catheter mapping was calculated for various distances from the coronary sinus orifice for adults of different ages and body weights. In adults, accessory pathways located in the proximal 1.5 cm of the coronary sinus are almost always in the posterior septum. Those located between 1.5 and 3 cm from the coronary sinus orifice may be in either the left free wall or the posterior septum, and those located greater than 3 cm from the coronary sinus orifice are almost invariably in the left free wall.

Adolescent↗
PubMed1991

Maintenance of functional activity of human pulmonary arteries after cryopreservation.

1. Human intrapulmonary arteries have been investigated in vitro in fresh tissue or after storage at -190 degrees C in foetal calf serum containing 1.8 M dimethyl sulphoxide. 2. After cryopreservation of the arteries, maximal contractile force was reduced to 76%. This was assessed by the responses (in g) to 10 nM of the thromboxane analogue, U 46619. 3. Constricting agonists such as noradrenaline, 5-hydroxytryptamine, histamine and U 46619 stimulated fresh and frozen/thawed arteries producing pD2 values similar to the respective values determined on fresh tissues. 4. Endothelium-independent relaxant responses of U 46619-precontracted arteries to prostacyclin (PGI2), aminophylline and papaverine were generally unchanged after storage. The same was true for relaxant response to the potassium channel activator P-1075 whereas the pD2 values for SDZ PCO 400, RP 49356 and cromakalim were somewhat diminished. 5. Nevertheless, a significant correlation was obtained when the apparent pD2 values for all agonists on fresh and frozen/thawed tissues were compared (P less than 0.001). 6. The evidence suggests that after cryopreservation of human intrapulmonary arteries at -190 degrees C, mechanisms of both contraction and relaxation are well-maintained.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1991

Euthanasia: the way to a peaceful end?

Euthanasia is an emotive subject, and one in which the line between what is legal and illegal is often blurred. Nurses need to tackle the issue personally and professionally to ensure they deliver care that is in their patients' interests.

Double Effect Principle↗
PubMed1990

Atomic veterans and their families: responses to radiation exposure.

In-depth interviews with seven atomic veterans and their families indicated powerful psychological effects on all family members from exposure to low-level ionizing radiation. Four themes emerged: the invalidation of their experiences by government and other authority figures; family concerns about genetic effects on future generations; family members' desire to protect each other from fears of physical consequences; and desire to leave a record of their experiences to help prevent future suffering.

Abnormalities, Radiation-Induced↗
PubMed1989

Ecstasy abuse.

Explore the source record for details and available documents.

3,4-Methylenedioxyamphetamine↗
PubMed1989

Four cases found at screening in general practice.

Individual cases can influence GPs more than carefully documented statistical arguments from population surveys. These four case histories illustrate that both specific and opportunistic screening may be needed if all patients at risk are to be identified.

Adult↗
PubMed1989

2(1H)-quinolinones with cardiac stimulant activity. 2. Synthesis and biological activities of 6-(N-linked, five-membered heteroaryl) derivatives.

A series of 6-(N-linked, five-membered heteroaryl)-2(1H)-quinolinone derivatives was synthesized and evaluated for cardiotonic activity. Most compounds were prepared by sulfuric acid catalyzed cyclization of an N-(4-heteroarylphenyl)-3-ethoxypropenamide or by condensation of a 2-amino-5-heteroarylbenzaldehyde or -acetophenone derivative with the ylide derived from triethyl phosphonoacetate. In anesthetized dogs, 6-imidazol-1-yl-8-methyl-2(1H)-quinolinone (3; 25 micrograms/kg) produced a greater increase in cardiac contractility (percentage increase in dP/dt max) than alternative 6-(five-membered heteroaryl)-substituted analogues (4-8). Introduction of 4-methyl (10) or 2,4-dimethyl (13) substituents into the imidazole ring of 3 produced a marked increase in inotropic activity, and these compounds were some 10 and 5 times more potent than milrinone. Most of these quinolinones also displayed positive inotropic effects (decrease in QA interval) in conscious dogs after oral administration (0.0625-1 mg/kg) and in many cases (3, 5-7, 9, 11, 13, 16) there was little difference in activities at both the 1- and 3-h time points. Compound 13 (62.5, 125, 250 micrograms/kg po) demonstrated dose-related cardiac stimulant activity which, in contrast to milrinone, was maintained over the whole 7-h test period. No changes in heart rate were detected at any dose level and compounds 3, 9, 10, and 13 also displayed high selectivity for the stimulation of cardiac contractile force rather than heart rate in the Starling dog heart-lung preparation. Increases in dP/dt max of approximately 50% were accompanied by heart rate changes of less than 10 beats/minute. Physicochemical measurements gave a log P of 1.64 for 13 with pKa values of 7.13 +/- 0.04 and 11.5 +/- 0.2 for the imidazole and quinolinone moieties, respectively. X-ray structural analysis of 13 showed the imidazole and quinolinone rings at 52 degrees to one another in close agreement with the minimum-energy conformation (30 degrees) suggested by PCILO calculations. 6-(2,4-Dimethylimidazol-1-yl)-8-methyl-2-(1H)-quinolinone (13, UK-61,260) is currently undergoing phase II clinical evaluation in congestive heart failure patients.

Animals↗
PubMed1988

2(1H)-quinolinones with cardiac stimulant activity. 1. Synthesis and biological activities of (six-membered heteroaryl)-substituted derivatives.

A series of (six-membered heteroaryl)-substituted 2(1H)-quinolinones (1) was synthesized, and structure-activity relationships for cardiac stimulant activity were determined. Most compounds were prepared by acidic hydrolysis of a heteroaryl-2-methoxyquinoline obtained by palladium-catalyzed cross-coupling methodology. Direct reaction of a pyridinylzinc reagent with a 6-haloquinolinone also proved successful. In anesthetized dogs, 6-pyridin-3-yl-2(1H)-quinolinone (3; 50 micrograms/kg) displayed greater inotropic activity (percentage increase in dP/dt max) than positional isomers (2, 4-6), and potency was maintained with either mono- (13, 15) or di- (16) alkylpyridinyl substituents. Introduction of a 4- (24) or 7- (25) methyl group into 3 reduced inotropic activity, whereas the 8-isomer (26) proved to be the most potent member of the series. Compound 26 and the 2,6-dimethylpyridinyl analogue (27) were approximately 6 and 3 times more potent than milrinone. Several quinolinones displayed positive inotropic activity (decrease in QA interval) in conscious dogs after oral administration (1 mg/kg), and 26, 27 were again the most potent members of the series. Compound 27 (0.25, 0.5, 1.0 mg/kg po) demonstrated dose-related cardiac stimulant activity, which was maintained for at least 4 h. No changes in heart rate were observed. Compounds 3, 4, 26, and 27 also selectively stimulated the force of contraction, rather than heart rate, in the dog heart-lung preparation. For a 50% increase in dP/dt max with 27, heart rate changed by less than 10 beats/min. In norepinephrine contracted rabbit femoral artery and saphenous vein, 27 produced dose related (5 X 10(-7) to 5 X 10(-4) M) vasorelaxant activity. The combined cardiac stimulant and vasodilator properties displayed by 27, coupled with a lack of effect on heart rate, should be beneficial for the treatment of congestive heart failure.

Animals↗
PubMed1988

Benzodiazepine abuse and management of anxiety in the community.

Medication is largely inappropriate in the management of anxiety, and benzodiazepines are not apparently effective in the minor affective disorders commonly seen in general practice (Catalan and Gath, 1985). Enough has been said to indicate that other measures are likely to be more helpful and to reduce the tendency to prescribe benzodiazepines. The taking of these drugs threatens to become epidemic and while medical agencies are by no means the only sources, sensible prescribing will go--and may already have gone, as the DHSS (1986) figures suggest--some way toward limiting consumption of these drugs. The DHSS needs to record more specific data relating to benzodiazepine use and abuse. Comparative trials of benzodiazepines and alternative non-benzodiazepine methods of anxiety management need to be set up as matter of urgency. The (no doubt) false impression that the pharmaceutical industry is dragging its feet in planning and sponsoring such trials should be speedily dispelled. Benzodiazepine prescribing, if it increases, may well in itself become a major danger to public health.

Anti-Anxiety Agents↗