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Biomedical subjects

T H Morris

Publications and source records attributed to T H Morris.

13 recordsLinked to original sources
PubMed1989

[Neutrophil defense against bovine uterine infections].

The killing ability of bovine peripheral blood neutrophils did not vary during the oestrous cycle. Administration of sex steroids to ovariectomised cows reduced the intrinsic killing ability of neutrophils but enhanced the opsonising ability of serum. Exudate from experimental uterine infection with Corynebacterium pyogenes and Fusobacterium necrophorum impaired neutrophil function, probably as a result of the action of bacterial leucotoxins.

Animals↗
PubMed1987

Rapid, single-step isolation of equine neutrophils on a discontinuous Percoll density gradient.

A rapid single-step procedure for isolation of equine neutrophils (PMNS) from peripheral blood is described. A discontinuous gradient of two Percoll solutions (densities of 1.087 kg litre-1 and 1.108 kg litre-1 was used. The PMNS were isolated to more than 95 per cent purity with a viability of more than 99 per cent and a cell recovery of more than 83 per cent. The method used was rapid and reproducible and the equipment required is relatively simple. The function of the recovered cells was assessed in a chemotactic assay using a modified Boyden chamber technique.

Animals↗
PubMed1986

Cambridge intake.

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Education, Veterinary↗
PubMed1984

Different steric characteristics of beta 1- and beta 2-adrenoceptors.

beta-Adrenoceptors of lung (75% beta 2) and heart (95% beta 1) of calf were labelled with 3H-(-)-propranolol. The stereoisomers of 10 ligands were used to inhibit the binding of 3H-(-)-propranolol to membrane particles. The affinity ratio of stereoisomers is consistently greater for beta 1-adrenoceptors than for beta 2-adrenoceptors, regardless of whether the ligands are agonists, partial agonists or antagonists. The beta 1-adrenoceptor appears to possess stricter steric requirements than the beta 2-adrenoceptor. This property may prove helpful in differentiating the beta-adrenoceptor subtypes during receptor solubilization and purification.

Animals↗
PubMed1982

An initial characterization of human heart beta-adrenoceptors and their mediation of the positive inotropic effects of catecholamines.

The positive inotropic effects of catecholamines were studied on samples of ventricular myocardium taken from patients undergoing open heart surgery. The adenylyl cyclase and binding of 3H-(-)-bupranolol were examined in membrane particles prepared from similarly obtained samples. The equilibrium dissociation constant (KD) for (-)-bupranolol was estimated in 4 ways: blockade of the positive inotropic effects of catecholamines, blockade of the stimulation of the adenylyl cyclase by catecholamines, saturation binding of 3H-(-)-bupranolol, inhibition of the binding of 3H-(-)-bupranolol by its unlabeled stereoisomers. The estimates of KD fall in the range 0.5-1.4 nmol/l. The stereo-selectivity ratio (KD (+)-isomer/KD (-)-isomer) is 73. Both values for bupranolol are very similar in cat and man. The inotropic potency of (-)-noradrenaline is nearly 2 orders of magnitude higher in cat heart tissues than in tissues from human hearts. The difference in inotropic potencies between species is only partially accounted for by the five-fold lower potency of (-)-noradrenaline for the human heart adenylyl cyclase as compared to the cat enzyme.

Adenylyl Cyclases↗