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Biomedical subjects

L J Greene

Publications and source records attributed to L J Greene.

At least 55 records · Page 3Linked to original sources
PubMed1978

Chromatographic determination of angiotensin-converting enzyme and angiotensinase activity.

An analytical method utilizing an automatic amino acid analyzer is described for the separation, identification, and measurement of 5 to 50 nmol of angiotensin I, angiotensin II, [Des-Phe8]angiotensin II, Phe-His-Leu, His-Leu, isoleucine, leucine, tyrosine, and phenylalanine. Aminex A-5 cation-exchange resin (0.9 x 15 cm) is sequentially eluted with three sodium citrate buffers: pH 3.25, 0.2 N; pH 4.85, 0.54 N, and pH 6.5, 0.39 N at 60 and 80 degrees C. Reaction with ninhydrin is used for detection. This chromatographic system was used to determine angiotensin-converting enzyme activity and the angiotensinase activity of rabbit brain endopeptidase B. In each assay, the unhydrolyzed substrate and both products were measured simultaneously in one step without pretreatment of the hydrolysate. Products were recovered in 1:1 molar ratios and the overall recovery of an hydrolyzed substrate of products was quantitative.

Amino Acids↗
PubMed1978

Comparison of the kininogenase activity of human pancreatic trypsins and porcine Kallikrein on Met-Lys-bradykinin and human plasma kininogen.

Human trypsins 1 and 2 both converted Met-Lys-bradykinin to bradykinin and released bradykinin from kininogen in human plasma as measured by bioassay with the isolated guinea pig ileum. Porcine kallikrein did not act on Met-Lys-bradykinin and released kallidin from human kininogen. Since human trypsin 1 is only partially and trypsin 2 completely inhibited by soybean trypsin inhibitor, these data show that the criterion of susceptibility to soybean trypsin inhibitor cannot be used to discriminate between trypsin and kallikrein of different species.

Animals↗
PubMed1977

Isolation of myocardial depressant factor from plasma of dogs in hemorrhagic shock.

Starting with 31 of plasma from dogs in hemorrhagic shock, we have purified the myocardial depressant factor and found that the activity is separate from salts and free amino acids. Moreover, the myocardial depressant factor is present in shock plasma in concentrations of about 1 nmol/ml of plasma. The depressant factor exists as multiple chromatographic forms. The best characterized forms are the anionic forms. A preliminary amino acid composition of the anionic forms has been obtained. These findings should allow more rapid processing of plasma containing high myocardial depressant factor activity to separate the factor and to completely identify this small peptide of great physiologic interest.

Amino Acids↗
PubMed1975

Radioimmunoassay of canine growth hormone: enzymatic radioiodination.

A sensitive radioimmunoassay is described for the measurement of plasma concentrations of canine growth hormone (cGH) as low as 0.25 ng/ml. The assay utilizes enzymatically iodinated cGH and the double antibody technique. The mean plasma concentration of growth hormone in the normal dog after overnight fast is 1.75 plus or minus .17 ng/ml. Exogenous cGH was cleared from the plasma of both the normal and hypophysectomized dog with a mean half-life of 25.6 plus or minus 1.0 min and was distributed in a volume equal to 8.9% of the body weight. Insulin hypoglycemia produced a 3- to 5-fold increase in plasma GH in 4 of 6 dogs and arginine infusion failed to produce a statistically significant rise.

Animals↗