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At least 19 recordsLinked to original sources
PubMed1979

High-performance liquid chromatographic analysis of biogenic amines in biological materials as o-phthalaldehyde derivatives.

A remarkably sensitive, simple and selective reversed-phase high-performance liquid chromatographic (HPLC) method has been developed, allowing, for the first time, the direct measurement of histamine, norepinephrine, octopamine, normetanephrine, dopamine, serotonin and tyramine in a single sample of plasma (2 ml), tissue (0.2 g), or urine. The biogenic amines were modified by pre-column derivatization with o-phthalaldehyde which stabilizes the molecules, aids in extraction, and improves HPLC detection at the nanogram level. To minimize losses during the sampling procedure a careful collection procedure was designed. We developed a simple sample cleanup in which the samples were thawed, neutralized with KOH, immediately derivatized, extracted into ethyl acetate (EtOAc) and then chromatographed by HPLC. The derivatives were stable in EtOAc for more then 24 h. Interfering amino acids were removed from the EtOAc by partitioning twice with Na2HPO4 buffer (pH 10.0). Complete separation was achieved in ca. 60--90 min on a muBondapak phenyl column using a stepwise gradient of acetonitrile and/or methanol-phosphate buffer (pH 5.1). A variable wavelength fluorometer with a 5-microliter flow-cell was used (excitation 340 nm; emission 480 nm). Linearity ranged from 200 pg to 50 ng onto the column. Precision (R.S.D.) for retention times was 1% and for derivatization and injection 2.5%. Recoveries of the seven biogenic amines from plasma spiked with 25 ng/ml averaged 70%, with a relative standard deviation of 6%. Separation studies were also done using a muBondapak C18 column. The effects of various eluents are presented. Gas-liquid chromatography was also investigated but lacked the sensitivity achieved by HPLC. The HPLC method is used routinely for the determination of biogenic amines in plasma from pigs with malignant hyperthemia and thermally stressed bovine. Significant differences in levels of biogenic amines were noted between stressed and non-stressed animals. Data on rat brain tissue samples were compared with the trihydroxyindole method and canine heart tissue was analyzed for ventricular norepinephrine and dopamine. Application of the method to urine from normal persons and a patient with a brain tumor has been demonstrated.

Animals↗
PubMed1979

PEP A9, a new, unstable variant in the peptidase A system.

A rare peptidase A variant, tentatively designated PEP A9, was observed in six members of a German family, indicating autosomal codominant inheritance. The electrophoretic mobility is similar to that of PEP A 3-1, but it has very low in vivo stability. There is no apparent association with a disease state. A simple and sensitive staining reagent for PEP A was found in o-phthalaldehyde.

Adult↗
PubMed1979

An improved and easy technique for polyamine determination in biological samples. Application to cell-free system from hypertrophied rat heart.

An accurate, improved cation-exchange chromatographic method using o-phthalaldehyde and ultraviolet detection at 280 nm for the determination of free polyamines (putrescine, spermidine, spermine) has been developed. Different samples, such as the 105,000 g supernatant of reticulocyte or heart muscle, and KCl ribosomal wash containing initiation factors, can be analysed. The minor modification of reagents results in a good precision and sensitivity, which is demonstrated by a relative standard deviation of 5--9% and recoveries of 98%. This technique is of particular interest because it allows polyamine determination in biological samples with high concentrations of salt.

Animals↗
PubMed1977

Interspecies homology of RNA tumor virus proteins.

We report the application of a highly sensitive column chromatographic technique to the comparison of tryptic peptide maps of some RNA tumor virus proteins. By combining microbore ion-exchange chromatography with a sensitive fluorescent assay using o-phthalaldehyde, we obtained high-resolution peptide maps starting with only microgram amounts of protein. Our discovery of coincident peptides from the 15,000 and 30,000 molecular weight proteins from murine and feline leukemia viruses supports serological evidence for interspecies antigenic determinants; coincident peptides were also found for the 10,000 molecular weight proteins from these viruses, although immunochemical data did not reveal interspecies determinants. The relatively large number of coeluting peptides found in the 15,000 and 10,000 molecular weight proteins is strong evidence for the existence of homology.

Avian Leukosis Virus↗
PubMed1979

Separation of D and L amino acids by liquid chromatography: use of chiral eluants.

An aqueous eluant containing a chiral copper-proline complex effects the separation of underivatized amino acid enantiomers on an ion-exchange column. The stereoselectivity is ascribed to differences in stability of the diastereomeric amino acid-copper compexes formed in solution. A simple change in the chirality of the eluant reverses the order of the enantiomer elution. For detection and quantification of picomole amounts of amino acids, the eluant is monitored for fluorescence after reaction with o-phthalaldehyde, a reagent insensitive to proline but highly sensitive for amino acids containing a primary amino group.

Amino Acids↗
PubMed1975

Fluorimetric determination of dipeptidyl carboxypeptidase. (angiotensin-I-converting enzyme).

A fluorimetric assay of dipeptidyl carboxypeptidase is described. It involves incubation at 37 degrees C with the substrate, Z-Phe-His-Leu, and reaction of the dipeptide His-Leu which is released upon enzymatic hydrolysis, with o-phthalaldehyde to yield a fluorescent compound. The method is simple, precise and sensitive. The assay in serum is conveniently performed on 20 mul samples. Normal values in human serum range from 0.04 to 0.22 U/l.

Benzyl Compounds↗
PubMed1976

[The endocrine cells of the gastrointestinal epithelium and the metabolism of biogenic amines in the gastrointestinal tract (author's transl)].

After a review on the historical development of morphological investigations of entero-endocrine cells, dating back to 1870, a detailed synoptical review of the current stage of findings in this field is given. At the present time nine different endocrine cell types can be distinguished in the epithelium of the gastrointestinal tract. Criteria for this differentiation are properties concerning specific staining methods, aldehyde-induced fluorescence, immunohistochemistry, and ultrastructure. From present results it is obvious that distinct cell types are responsible for the synthesis of defined polypeptide hormones (e.g. gastrin, secretin, enterogastrone). The metabolism of amines, in relation to the endocrine cells of the gastrointestinal tract is of particular interest here. Points investigated include the uniqueness of endocrine cells, with regard to the metabolism of biogenic amines ("APUD-cells") and the possibility of serotonin synthesis by a definite cell type, i.e. by the EC-cell ("enterochromaffin" cell). In our experimental animal, male Wistarrats, seven different entero-endocrine cell types can be discerned by ultrastructural means: EC-, ECL-, G-, AL-, EG-, D- and D1-cells. The I-cell (found in other species) can hardly be distinguished from the AL-cell by ultrastructural means and the S-cells, as found in other species, are not to be found at all. Only some of the cited cell types can be seen by fluorescence microscopy. After formaldehyde-treatment of the tissue, the "enterochromaffin" cell shows a yellow, serotonin-specific fluorescence. This cell corresponds in shape, number and distribution to the ultrastructurally defined EC-cell. EC-cells are found predominantly in the pyloric region and the duodenum and less frequently in the middle- and hindgut and the cardiac region; seldomly EC-cells are encountered in the oxyntic gland area of the stomach. In the rat gastro-intestinal tract, number and fluorescent intensity of EC-cells does not always correspond with the serotonin content of a certain region--sometimes the level of serotonin is largely determined by the mast cells, which in the rat also contain serotonin. For example, the high serotonin content of the oxyntic gland area, which contains very few EC-cells, has to be contributed nearly exclusively to mast cell serotonin. Mast cells can be domonstrated by fluorescence microscopy, due to their histamine content, after treatment of the tissue with o-phthalaldehyde (OPD). It seems likely that the histamine content, especially that of the so-called "atypical mast cells" of the mucosa, is inversely related to their respective serotonin content. --In addition to mast cells, OPD-treatment leads to a fluorescence in some of the entero-endocrine cells of the gastrointestinal epithelium. In the gastric epithelium these fluorescing cells should be regarded as histamine-containing ECL-cells and glucagon-containing AL-cells while in the colonic epithelium they are considered to be glucagon-containing AL-cells...

5-Hydroxytryptophan↗
PubMed1979

The role of cell-fixed calcium in histamine release by compound 48/80.

1. Histamine release by compound 48/80 was substantially reduced in a time-dependent manner (maximum at 30 min) by pre-incubating mast cells in calcium-free medium at 37 degrees C but not at 2 degrees C. This effect was optimal at pH 7.0 to 7.5. 2. The re-introduction of calcium (0.1 to 3 mmol/l) restored histamine release to the control value; this effect was independent of temperature. 3. Strontium (1 to 30 mmol/l) partially reversed the effect of calcium deprivation but the same concentrations of barium and magnesium depressed histamine release even further. Magnesium (3 to 15 mmol/l) antagonized the effect of calcium replacement. 4. Results suggest that the level of cell-fixed calcium involved in compound 48/80-induced histamine release may be controlled by the combination of rapid passive influx and slow active efflux.

Animals↗