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Biomedical subjects

S Poole

Publications and source records attributed to S Poole.

At least 145 records · Page 8Linked to original sources
PubMed1988

Sensitive and specific immunoradiometric assays for human interleukin-1 alpha.

In order to estimate human IL-1 alpha in physiological samples we have established sensitive and specific immunoradiometric assays using monoclonal and polyclonal antibodies. Solid phase assays employing two different monoclonal antibodies were suitable for estimating rDNA derived IL-1 alpha but were relatively insensitive. Sensitivity was increased by using a monoclonal antibody to capture antigen and 125I-labelled polyclonal sheep antibodies to develop the assay. This assay could detect as little as 20pg/ml IL-1 alpha and could be used for assaying antigen in monocyte supernatants, in human skin extracts and in joint fluid from patients with inflammatory disease. It was entirely specific for IL-1 alpha and was unaffected by non-IL-1 alpha components present in serum. It is therefore suitable for monitoring IL-1 alpha concentrations in the circulation of patients undergoing therapy with the monokine.

Antibodies, Monoclonal↗
PubMed1988

Preparation of monoiodinated interleukin-1 beta and its use in a radioimmunoassay.

Polyclonal anti-interleukin-1 beta (IL-1 beta) sera raised in sheep and in rabbits bound to unlabelled IL-1 beta. IL-1 beta radioiodinated using chloramine-T or Bolton-Hunter procedures was bound by the anti-IL-1 beta sera but was not displaced by unlabelled IL-1 beta suggesting that IL-1 beta was damaged during iodination procedures, resulting in alterations to the immunological properties of the tracer. Iodination using the mild oxidant N-bromosuccinimide, followed by extensive tracer purification to remove the unlabelled IL-1 beta, produced a tracer with a specific activity of 89 microCi/micrograms (0.83 atoms iodine/molecule IL-1) which was fully displaced by unlabelled IL-1 beta, allowing the development of a sensitive and specific radioimmunoassay for IL-1 beta. The radioimmunoassay has been used to quantify intracellular IL-1 beta and IL-1 beta release by peripheral blood monocytes stimulated with endotoxin.

Animals↗
PubMed1988

Assay of pyrogenic contamination in pharmaceuticals by cytokine release from monocytes.

In 1984 it was reported that a batch of human recombinant growth hormone which had passed the rabbit pyrogen test and a Limulus amoebocyte lysate (LAL) test was pyrogenic in man (1). Further, it was shown that the growth hormone caused human monocytes to release leukocyte pyrogen which evoked fevers in rabbits (1). Leukocyte pyrogen is believed to comprise of a mixture of (at least) 2 lymphokines with potent pyrogenic and inflammatory activities, interleukin-1 (IL-1) and Tumour Necrosis Factor (TNF), which are synthesized and released by activated peripheral blood monocytes. The development at NIBSC of sensitive and specific bioassays and immunoassays of IL-1 (2) and TNF (3) have permitted a new type of pyrogen test based on the in vitro release by human monocytes of the lymphokines IL-1 and TNF. Studies are underway to evaluate the suitability of monocytic cell lines, rather than human monocytes, since these require a time-consuming and labour intensive preparation. Investigations are in progress to evaluate the suitability of the above "monocyte test" for pyrogen to replace or complement the rabbit pyrogen test which is routinely applied to biological medicines. The new method has already proved useful in detecting pyrogenic contamination of a large volume parenteral medicinal product which passed the rabbit pyrogen test but caused adverse reactions in patients.

Cells, Cultured↗
PubMed1987

A simple sensitive bioassay for interleukin-1 which is unresponsive to 10(3) U/ml of interleukin-2.

A subclone, NOB-1, of the mouse EL-4 line constitutively produces very little interleukin-2 but in response to interleukin-1 produces high concentrations of interleukin-2. Co-stimulation with mitogen, phorbol esters or calcium ionophores was not required. NOB-1 is not responsive to tumour necrosis factor alpha, tumour necrosis factor beta, interferon gamma and lipopolysaccharide. The NOB-1 line was used in conjunction with a CTLL line to detect less than 1 pg/ml interleukin-1. Rapid assay was performed by co-culturing the EL-4 cells with CTLL cells. By incorporating a pre-incubation step, followed by thorough washing of the EL-4 cells, responses to interleukin-1 were maintained, but interleukin-2 had no effect. The assay was used to detect interleukin-1 in serum samples and to evaluate neutralizing antisera to interleukin-1.

Animals↗
PubMed1986

Bioavailability in rats of human recombinant tissue plasminogen activator after subcutaneous and intramuscular injection.

The bioavailability of human recombinant tissue plasminogen activator (rt-PA) in rats was measured after subcutaneous (s.c.) and intramuscular (i.m.) injection. Rt-PA was absorbed after both i.m. and s.c. injection, giving peak plasma concentrations within 30 min and 1 h, respectively, with detectable concentrations up to 6 h. These peak values of bioavailable t-PA were obtained in a functional fibrin plate assay of euglobulin precipitates and expressed as +88% and +243% (for s.c. and i.m. routes respectively) above basal rat fibrinolytic activity. Prior injection of rt-PA, s.c. or i.m., significantly reduced the weights of thrombi induced in the inferior vena cava after injection.

Animals↗
PubMed1986

Detection of endotoxin in mice by measurement of endotoxin-induced changes in plasma concentrations of zinc and of the acute-phase protein serum amyloid P-component.

Preparations of six bacterial endotoxins reduced plasma concentrations of zinc and increased concentrations of the acute-phase protein serum amyloid P component (SAP) in mice. The changes were sufficiently sensitive to permit use of either response in tests for endotoxin and hence for pyrogenic contamination.

Acute-Phase Proteins↗
PubMed1985

Effects of desipramine on cardiovascular responses of rats to stimulation of the baroreceptor reflex and of central adrenoceptors.

Phenylephrine (0.4-2.0 micrograms 300 g-1), injected intravenously, evoked similar dose-dependent increases in blood pressure in untreated rats and in rats treated with desipramine (10 mg kg-1 day-1 for 4 weeks). The (dose-dependent) reflex fall in heart rate to the blood pressure responses were smaller in the rats treated with desipramine. Treatment with desipramine did not affect the bradycardia evoked by intrahypothalamic injection of phenylephrine (10 micrograms). After treatment with desipramine, the hypotension evoked by intrahypothalamic injection of isoprenaline (10 micrograms) was enhanced whereas the evoked tachycardia was diminished.

Adenylyl Cyclases↗
PubMed1985

Growth hormone-releasing factor analogue (hGRF1-29NH2): immunoreactive-GRF plasma levels after intravenous and subcutaneous administration.

A homologous radioimmunoassay (RIA) system for human growth hormone-releasing factor 1-29NH2 (hGRF 1-29-NH2) was developed and applied to the measurement of immunoreactive (IR) concentrations of the peptide in anaesthetized rats to determine some of its pharmaco-kinetics after i.v. and s.c. administration. Analysis of the biphasic disappearance curve of IR-hGRF-1-29NH2 from plasma after i.v. injection (10 micrograms) gave values for the half-lives of the initial distribution phase (alpha) and for the elimination phase (beta) of 1.9 +/- 0.2 min and 10.4 +/- 0.2 min respectively. There was rapid uptake of the peptide from the site of s.c. injection but comparison of areas under the plasma IR-hGRF1-29NH2/time curves showed that the estimated total amount in the circulation after s.c. injection was only 4% of that obtained after i.v. administration. A large degree of degradation of the peptide is indicated either at the site of injection or during transfer to plasma; this susceptibility to rapid breakdown is reflected in the short half-life of the peptide in the circulation. Therefore the measurement of the above parameters is a prerequisite when assessing potency of GRF analogues in-vivo and when implementing suitable dosage regimens for clinical purposes.

Animals↗
PubMed1984

Effect of bacterial endotoxin on body temperature, plasma zinc and plasma concentrations of the acute-phase protein serum amyloid p component in mice.

Bacterial endotoxin and lipid A evoked dose-dependent increases in body temperature and plasma SAP concentrations and dose-dependent falls in plasma zinc concentrations in mice. The respective sensitivities of the three variables to lipid A or to whole endotoxin had the relation SAP greater than Zinc much greater than body temperature; zinc and SAP responses were evoked by less than 1 ng lipid A/endotoxin. Pretreatment with indomethacin prevented only the temperature response to lipid A. Pretreatment with dexamethasone did not affect the temperature response but diminished the zinc response and enhanced the SAP response to lipid A.

Amyloid↗
PubMed1983

Cardiovascular responses of rats to intrahypothalamic injection of carbachol and noradrenaline.

Carbachol (0.1-2 micrograms) and noradrenaline (5-20 micrograms) injected into the anterior hypothalamus of unanaesthetized unrestrained rats evoked dose-dependent falls in heart rate and increases in arterial blood pressure. When the above amine injections were repeated in rats anaesthetized with chloral hydrate, sodium pentobarbitone or halothane the evoked bradycardias were usually smaller and the changes in arterial blood pressure more variable. The cardiovascular responses to carbachol (1 microgram) and to noradrenaline (10 micrograms) were antagonized by intrahypothalamic injection of atropine (1 microgram) and phentolamine (10 micrograms), respectively. The bradycardias evoked by carbachol (1 microgram) and by noradrenaline (10 micrograms) were abolished by pretreatment with intra-arterial injection of methyl atropine (100 micrograms 100 g-1). The hypertensive responses to carbachol (1 microgram) and to noradrenaline (10 micrograms) were reduced by pretreatment with intra-arterial injection of thymoxamine (500 micrograms 100 g-1).

Anesthesia↗
PubMed1980

Analysis of the multigene family coding the developmentally regulated carbohydrate-binding protein discoidin-I in D. discoideum.

Using recombinant DNA technology, we have isolated chimeric plasmids carrying genomic or cDNA sequences complementary to mRNA encoding the developmentally regulated carbohydrate-binding protein Discoidin-I. The protein is encoded by a 4-5 member multigene family. Mapping of the genomic sequences by DNA blot hybridization suggests that several of the genes are closely linked. RNA excess hybridization kinetics indicate that Discoidin-I mRNA is found in less than one copy per gene per cell during vegetative growth, and increases 500-1000 fold during the first 6 hr of development. The Discoidin-I mRNA concentration decreases during later stages of development. mRNA complementary to the genes shows two bands of -1.0-1.1 kb on acrylamide gels, indicating heterogeneity either in the genes or in mRNA processing.

Base Sequence↗
PubMed1979

Effects of noradrenaline and carbachol on temperature regulation of cold-stressed and cold-acclimated rats.

1 Noradrenaline (20 micrograms) and carbachol (1 microgram) injected into the anterior hypothalamus of rats at an ambient temperature of 23 degrees C evoked significant falls in core temperature and increases in tail temperature. 2 When rats were cold-stressed (4 degrees C for 90 min) or cold-acclimated (4 degrees C for 4 weeks) and the above amine injections repeated, only carbachol evoked significant falls in core temperature and neither amine increased tail temperature. 3 Central injections of noradrenaline and carbachol also evoked increases in plasma glucose concentrations but not plasma non-esterified fatty acid (NEFA) concentrations in control, acutely cold-stressed and cold-acclimated rats. 4 Although concentrations of plasma glucose and blood lactate of rats were unaffected by cold exposure to 4 degrees C for 1 to 28 days, glucose oxidation rate of both cold-stressed and cold-acclimated rats was significantly greater than in rats at 23 degrees C. Concentrations of plasma NEFA were increased after 1 to 28 days of cold exposure.

Acclimatization↗
PubMed1979

Effects of noradrenaline and carbachol on temperature regulation of rats.

1 Noradrenaline (0.2 to 20 micrograms) and carbachol (0.1 to 1 microgram) injected into the preoptic/anterior hypothalamic area, evoked dose-dependent falls in core temperature at all sites tested, followed in most experiments by delayed increases that were not dose-related. Muscarine (0.1 to 10 microgram) produced effects similar to those evoked by carbachol. 2 These falls in core temperature were associated with increases in tail temperature, locomotor activity and CO2 elimination (a measure of metabolic rate). 3 The temperature responses to noradrenaline (10 microgram) and to carbachol (1 microgram) were antagonized by intrahypothalamic injections of phentolamine (10 microgram) and atropine (1 microgram), respectively. 4 Analysis of the temperature responses and their respective latencies indicates that carbachol-induced hypothermia was mediated by cholinoceptors in the anterior hypothalamus, whereas hypothermia after noradrenaline was mediated by adrenoceptors throughout the preoptic/anterior hypothalamic area. 5 Vasodilatation of the tail blood vessels contributed significantly to the hypothermia evoked by carbachol, and to that evoked by injections of noradrenaline into the anterior hypothalamus. 6 Hypothermia induced by noradrenaline injection into the preoptic area, was mediated by effector mechanisms additional to non-evaporative heat loss.

Animals↗