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Biomedical subjects

C J Coulson

Publications and source records attributed to C J Coulson.

17 recordsLinked to original sources

Total serum IgE and IgE antibodies specific to house dust mite found in two aged-matched cohorts of children with and without otitis media with effusion.

OBJECTIVES: To determine whether otitis media with effusion (OME) is associated with elevated serum immunoglobulin E (IgE) and IgE specific for house dust mite. DESIGN: Forty-seven children who had evidence of bilateral OME, both otoscopically and on tympanometry, on two separate occasions, 3 months apart were admitted for ventilation tubes. Forty-eight children admitted for minor eye surgery who had otoscopically normal ears and no history of middle ear problems were used as controls. Bloods samples were taken under anaesthesia. Total IgE and IgE radioallergosorbent test (RAST) to house dust mite was measured by the Pharmacia Unicap 100 system. The results from the two groups were compared. SETTING: Birmingham Children's Hospital. PARTICIPANTS: Children between the ages of 3 and 10. Children with Down's syndrome, cleft lip and palate, ciliary abnormalities, known immunodeficiencies and cardiac abnormalities were excluded. MAIN OUTCOME MEASURES: Total IgE and RAST to house dust mite. A RAST of >0.35 was taken to be positive. RESULTS: There was no statistical difference between the control and study groups for the total IgE. Six children from both study and control groups had a raised house dust mite RAST. There was no difference in the levels between either group. CONCLUSIONS: Our findings indicate that there is no direct relationship between OME and biochemical evidence of allergy, specifically to house dust mite.

Allergens↗

Pre-menstrual syndrome--are gonadotropins the cause of the condition?

It is proposed that premenstrual syndrome results from the action of elevated gonadotropin levels in various tissues of body other than their natural target organs. These levels are derived from an increased sensitivity to estrogen after pregnancy, childbirth, etc., particularly with respect to the positive feedback on gonadotropin release from the pituitary. Estrogen in conjunction with gonadotropin-releasing hormone (GnRH) releases excessive amounts of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) at ovulation and in the premenstrual phase (post-menopausal patients have greatly elevated gonadotropins and can also demonstrate cyclic symptoms). Gonadotropin action via adenylate cyclase in the adrenal cortex elevates cortisol, while antagonism of parathyroid hormone action on bone gives rise to hypocalcemia. The physiological and psychological symptoms may thereby be explained.

Adenylyl Cyclases↗

Hypoxic cell sensitization to radiation damage by a new radiosensitizer: cis-dichloro-bis(1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole-N3)platinum(II) (flap).

A new, stable platinum coordination complex (FLAP) containing the 5-nitroimidazole, metronidazole, has been prepared and characterized. The square-planar platinum(II) complex has two metronidazole molecules and two chlorine atoms in the cis configuration. The properties of FLAP differ significantly from metronidazole alone or other platinum complexes tested in the same system. It has a low toxicity towards Chinese hamster ovary cells and is a very effective radiosensitizer toward hypoxic cells in vitro: a one-h pretreatment with a non-toxic dose of 50 microM gave an enhancement ratio of 2.4. No potentiation of aerated cells to X-irradiation damage was observed after a similar schedule of pretreatment at the higher dose of 100 microM FLAP.

Animals↗

Correlation of hydrophobicity with protein binding for clorobiocin analogs.

A new method of equilibrium dialysis was used to measure the binding of analogs of clorobiocin (18631 R.P.) to human serum albumin. Binding constants and numbers of binding sites on human serum albumin were calculated from the binding data and were used to calculate the percentage of compounds free in equilibrium with 4% albumin. Partition coefficients between n-octanol and phosphate buffer (0.05 M, pH 7.4) also were measured. A positive linear correlation (r = 0.918, s = 0.240, and n = 10) was obtained between log (bound/free compound) and log partition coefficient.

Chemical Phenomena↗

Blood plasma binding of acebutolol and diacetolol in man.

1 Acebutolol or diacetolol were added to fresh human plasma in varying concentrations and their extent of binding at 25 degrees C measureed by an equilibrium dialysis technique. 2 The extent of binding for both compounds was shown to be very low, being 11-19% for acebutolol and 6-9% for diacetolol. 3 Partition coefficients were measured in an n- octanol/phosphate buffer (0.05M, pH 7.4) solvent system. For a cebutolol, P = 0.62 and for diacetol, P = 0.08. 4 The very low plasma binding is in accord with the hydrophilic partition coefficients of these compounds.

Acebutolol↗

A comparison of the pharmacological and biochemical properties of substrate-selective monoamine oxidase inhibitors.

1. M&B 9302, E-250, NSD 2023, and Lilly 51641, substrate-selective inhibitors of monoamine oxidase (MAO), and two non-selective inhibitors of MAO (tranylcypromine and phenelzine) have been compared in the rat for activity in (i) inhibiting rat brain monoamine oxidase in vitro and in vivo using tyramine, 5-hydroxytryptamine (5-HT) and benzylamine as substrates; (ii) increasing brain levels of noradrenaline (NA) and 5-HT and (iii) antagonizing tetrabenazine-induced sedation.2. Concentrations of M&B 9302 and Lilly 51641 required to produce 50% inhibition of 5-HT oxidation by brain mitochondrial MAO were 1.4 x 10(-8)M and 2.5 x 10(-7)M respectively. Higher concentrations were required to inhibit tyramine oxidation whilst benzylamine oxidation was inhibited only at concentrations above 10(-5)M.3. E-250 showed the reverse substrate-selectivity in inhibiting the oxidation of benzylamine at concentrations below that required to inhibit the oxidation of 5-HT. NSD 2023 showed little substrate selectivity in vitro.4. Qualitatively similar results were obtained in vivo, except that NSD 2023 showed more marked substrate-selectivity.5. All the inhibitors except E-250 produced a dose-related rise in brain 5-HT levels. Only phenelzine and Lilly 51641 showed a linear relationship between NA levels and dose.6. All the drugs antagonized, in dose-related fashion, the effects of tetrabenazine in reducing locomotor activity. E-250 and NSD 2023 failed to restore locomotor activity to control levels whilst in high doses the other inhibitors, when given before tetrabenazine, produced a considerable increase in locomotor activity.7. Antagonism of tetrabenazine sedation appears to be correlated with (a) inhibition of the enzyme species that oxidize 5-HT and NA but not with inhibition of the enzyme species that oxidize benzylamine; (b) the rise in brain 5-HT levels rather than NA levels.

Amines↗