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Biomedical subjects

M Hill

Publications and source records attributed to M Hill.

At least 451 records · Page 25Linked to original sources
PubMed1972

Quantitative analysis on isolated organs of the autonomic blocking properties of indoramin hydrochloride (Wy 21901).

1. Indoramin is a competitive alpha-adrenoceptor blocking agent on the guinea-pig isolated vas deferens and aortic strip; the pA(2) value on the aorta is 7.4.2. Indoramin is devoid of beta-adrenoceptor blocking activity on the guinea-pig isolated trachea (10(-4)M) and the Langendorff preparation of the rabbit heart (10(-6)M). It also has no adrenergic neurone blocking action on the Finkleman preparation of the rabbit small intestine (10(-5)M).3. On the Langendorff preparation of the rabbit isolated heart, indoramin (above 10(-6)M) has cardio-inhibitory properties similar to those of propranolol.4. On the guinea-pig isolated ileum (10(-5)M) and trachea (10(-6)M), indoramin is devoid of anticholinergic activity, but has a potent antihistamine action which satisfies the criteria for competitive antagonism; the pA(2) value for this antagonism on the ileum is 8.2.5. Indoramin antagonizes 5-hydroxytryptamine on the rat isolated fundus and ileum; the pA(2) value for the antagonism on the ileum is 6.0.

Adrenergic alpha-Antagonists↗
PubMed1970

Un nouveau colorant fluorescent pour la mesure du temps de relaxation brownienne des proteines.

Several authors have described the NBD-chloride (7-chloro-4-nitrobenzo-2-oxa-1,3-diazole) as a fluorogenic reagent of the amino groups and the sulfhydryl groups. It reacts rapidly with the trypsin to produce a stable and highly fluorescent conjugate. The determination of the labelled residues was made with thin layer chromatographies; the lysin residues were preferentially labelled.Fluorescence depolarization measurements of the conjugate were used to determine the brownian relaxation of the enzyme. The temperature dependence of the life-time is very strong and the corrected Perrin's plot demonstrates that the relaxation time of the enzyme decreases rapidly with the temperature.The conclusion is that the NBD-chloride can be used, like the DNS-chloride but is more reactive and stable and its fixation, on trypsin can be followed by measuring the absorbance of the dye at 470 nm.

Journal Article↗
PubMed1970

Activite trypsique a l'egard de certains substrats chromogenes.

Tryptic hydrolysis of different arginine nitroanilides was studied. Para-nitroanilide is the most readily hydrolyzed substrate, ortho derivative is 5 times less sensitive and meta derivative is a very weak substrate. When the benzoyl group bound on the N(alpha) arginine of BAPNA is replaced by a carbobenzoxy group (L-ZAPNA), the tryptic hydrolysis is increased by a factor of 3. With this latter substrate, the kinetic constants are determined for two forms, native and Nepsilon-acetylated of porcine and bovine trypsin. Evidence is presented that the rate of hydrolysis is both related to the global and local charges of the enzyme.

Journal Article↗