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Biomedical subjects

D B Gordon

Publications and source records attributed to D B Gordon.

At least 55 records · Page 3Linked to original sources
PubMed1981

Fast-atom-bombardment mass spectra of enkephalins.

The positive- and negative-ion mass spectra of [methionine]enkephalin and [leucine]enkephalin have been obtained by using a fast-atom-bombardment source described previously by Barber, Bordoli, Sedgwick & Tyler [(1981) J. Chem. Soc. Chem. Commun., in the press]. This technique has allowed the spectra to be obtained without conversion of the enkephalins into volatile derivatives. The fast-atom-bombardment spectra show good pseudo-molecular-ion sensitivity and fragmentation that can be interpreted on the basis of the known molecular structure.

Anions↗
PubMed1980

Increased pressor activity in incubated plasma of pregnant rabbits.

A study to measure the pressor activity which is generated in incubated plasma of pregnant and nonpregnant rabbits was performed by means of a recently modified bioassay technique. It was found that plasma of normal pregnant rabbits generated significantly higher amounts of active pressor principle (APP) than those generated by plasma of nonpregnant rabbits. The possible relevance of these results to blood pressure regulation during normal and abnormal pregnancies is discussed.

Animals↗
PubMed1980

Simultaneous measurement of PRA, PRC and PRR and the relation of renin reaction rate to renin substrate concentration.

We have altered the method for measuring plasma renin concentration (P.R.C.) originated by Haas, et al (7) by using radioimmunoassay of angiotensin I and avoiding the addition of extrinsic renin substrate. Thus modified, the method gives values for P.R.A. (plasma renin activity), P.R.C. (plasma renin concentration), and also P.R.R. (plasma renin reactivity), which is the rate of reaction of renin substrate in the plasma with added extrinsic renin. By applying this modified method to a wide variety of plasma samples and independently measuring plasma renin substrate concentration (P.R.S.) in the same samples, we found a good correlation between P.R.R. and P.R.S. Our results indicate that the rate of the renin - renin substrate reaction in human plasma is proportional to renin substrate concentration over a wide range of values up to 5000 ng angiotensin I/ml or higher. Thus, first order reaction kinetics with respect to substrate concentration is followed even at high substrate levels and the Km must be high. An additional finding was that pregnant women have elevated P.R.C. levels in contrast with women taking oral contraceptives who have P.R.C. levels lower than normal.

Alcoholism↗
PubMed1978

Renin lowers blood-pressure.

The hypothesis that increased plasma-renin tends to lower blood-pressure is proposed. Binding of renin to blood-vessel walls is postulated to have some vasodilator action which would oppose the usual blood-pressure-raising action caused by generation of angiotensin. Many of the effects of saralasin and of converting-enzyme inhibitor on blood-pressure in relation to concentrations of renin in blood plasma and in the kidneys seem to support this hypothesis.

Angiotensin II↗
PubMed1976

Plasma zinc levels in nephrectomized and ureteral ligated rats.

The effect of nephrectomy and ureteral ligation on the plasma zinc levels of zinc-supplemented and unsupplemented rats was studied. Bilateral nephrectomy, and to a greater extent bilateral ureteral ligation, resulted in a significant lowering of plasma zinc in the unsupplemented rats. Sham operation caused a lesser but significant lowering of plasma zinc which was not different from the effect of unilateral nephrectomy or unilateral ureteral ligation. Adding zinc to the drinking fluid of the bilateral nephrectomized rats raised their plasma zinc levels to that of sham-operated controls, but had no effect on the plasma zinc levels of the bilateral ureteral-ligated rats.

Animals↗
PubMed1975

Renin substrate in plasma of various mammalian species: electrophoresis on polyacrylamide gel.

The plasma of eight different species was subjected to electrophoresis on polyacrylamide gel, and the position of renin substrate was determined. There are considerable differences in the electrophoretic mobility of the renin substrates tested. Sheep substrate shows the slowest migration and mouse substrate the most rapid. The species tested appear to fall into two groups: slow-moving substrates occuring in the plasmas of sheep, cow, pig, and rabbit and fast moving substrates in man, dog, rat, and mouse. In most species only a single peak of renin substrate appeared, but in man and dog a minor peak was often observed in addition to the prominent major one. The classification of human renin substrate as an alpha-2-globulin is questioned.

Angiotensin II↗