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Biomedical subjects

D P Grettie

Publications and source records attributed to D P Grettie.

13 recordsLinked to original sources

Antibody to spermine: a natural biological constituent.

A protein that binds spermine specifically was separated from normal rabbit serum by affinity chromatography. Immunoelectrophoresis, the Ouchterlony immunodiffusion test, and gradient gel electrophoresis indicated that this protein has immunoglobulin characteristics and consists of several populations of antibodies to spermine. These were sequentially released from Sepharose-spermine gel by step-wise elution with solutions ranging in pH from 4 to 1. The binding constants varied from 5.0 x 10(8) to 11.1 x 10(8) liters per mole. These globulins did not react with monoacetylputrescine, L-ornithine, L-lysine, and histamine. Negligible cross-reactivity was detected with spermidine, putrescine, N8-monoacetylspermidine, cadaverine, and diaminopropane. Since perturbations in polyamine metabolism have been identified in several diseases, the study of extracellular polyamine homeostasis may reveal an important regulatory function for this protein.

Animals↗

Development of a specific antispermine antibody.

Highly specific antibody to spermine was produced in the rabbits by immunization with a spermine-thyroglobulin conjugate of high molar ratio (740:1). Cross-reactivity with spermidine was 1.4-2.2 percent and negligible with putrescine and other compounds of similar structure. The average affinity constant of five pools of antispermine rabbit antisera was Ka = 1.8 +/- 0.2 X 10(8) liter/mole.

Animals↗

Purification of rabbit antispermine antiserum by affinity chromatography.

Immunoglobulins G were isolated from a crude rabbit antispermine antiserum using a protein A-Sepharose CL-4B column. Affinity chromatography coupling spermine to the Sepharose matrix was employed for separation of antispermine antibodies from these immunoglobulins. Four fractions of antispermine antibodies were isolated by stepwise elution with solutions at pH range from 4 to 1. Binding constants were determined and cross-reactivity with other polyamines was tested for each fraction of antibodies. Highly specific antispermine antibodies were found in fraction IV.

Animals↗

1-N-Acetylspermidine: occurrence in normal human serum.

Using gas chromatography mass spectrometry following derivatization (N-trifluoroacetylation), 1-N-acetylspermidine was found to occur in normal human serum at a level of approximately 0.008--0.5 nmol ml(-1), i.e. about two orders of magnitude lower than the corresponding spermidine level. No evidence for the occurrence in serum of the isomeric 8-N-acetylspermidine was found. Mass spectra of authentic samples of trifluoroactylated 1-N- and 8-N-acetylspermidine are presented.

Acetylation↗

Radioimmunoassay of spermidine in human serum.

Specific antispermidine antibodies were produced following immunization of New Zealand white rabbits with a spermidine-thyroglobulin conjugate of high (greater than 200:1) hapten-carrier molar ratio. The harvested antispermidine rabbit antiserum was characterized and a radioimmunoassay procedure developed. The specificity of this antibody was tested against cadaverine, putrescine, spermine, monoacetylputrescine, N-8-acetylspermidine and other compounds of similar molecular structure. Negligible cross-reactivity was observed with putrescine (2.1%), cadaverine (0.6%), spermine (0.3%), diaminopropane (less than 0.1%), and no cross-reaction was found with monoacetylputrescine, N-8-acetylspermidine, histamine, L-lysine and L-ornithine. The spermidine values on serum of five healthy volunteers were determined by RIA and compared with values by gas chromatographymass spectrometry. Statistical evaluation of the results were highly agreeable. Antibody titer, intra-assay precision and analytical accuracy were tested. The assay requires only 20 microliter of serum and has picomole sensitivity. The sensitivity, specificity and small sample requirement make this procedure an effective tool for spermidine analysis.

Animals↗

Direct determination of polyamines in human serum by radioimmunoassay.

Antipolyamine antibodies were produced following immunization of New Zealand white rabbits with thyroglobulin spermine conjugate, using multiple-site injection and macrophage-harvesting techniques. The antispermine antibody in a radioimmunoassay system cross-reacted with spermidine (22%), putrescine (1%), diaminopropane (6%), and cadaverine (0.16%). No reaction with L-lysine, ornithine, or histamine was noted. Using this antibody, the radioimmunoassay for direct determination of serum polyamines was developed. A sensitivity of 200 pg was achieved on human serum samples. This radioimmunoassay would appear to be a useful tool for the detection and monitoring of a variety of pathophysiological states associated with abnormal polyamine metabolism, i.e., cancer.

Animals↗