Simultaneous fluorometric determination of intracellular polyamines separated by reversed-phase high-performance liquid chromatography

A reversed-phase HPLC technique in combination with fluorescent detection is described for simultaneous quantification of the precolumn Dansyl derivatives of intracellular amines. The derivatives were stable for at least one week, kept protected from the light at -20 degrees C. The detection limit was between 1 and 5 pmol for all tested polyamines. Serotonin coeluted with tryptamine. The method has a very good reproducibility for both, retention times and chromatographic peak areas. The average recovery of standard amine solutions added to cellular extracts was estimated to be higher than 90%. The described method enables a rapid, reliable and reproducible quantification of biogenic and related polyamines in biological fluids and tissues.

L-alanine transport by systems A and ASC in plasma membrane vesicles isolated from Ehrlich cells

Plasma membrane vesicles were prepared from Ehrlich cells using two-phase system compartmentation. These vesicles accumulated L-alanine mainly by means of Na(+)-dependent transport systems A and ASC. The kinetic of both transport systems could be elucidated by specific inhibition of system A with methyl-aminoisobutyric acid.

Sodium-dependent L-serine transport in plasma membrane vesicles isolated from Ehrlich cells by two-phase compartmentation

Plasma membrane vesicles were prepared from Ehrlich cells using two-phase system compartmentation. The highly pure plasma membrane vesicles obtained presented a negligible mitochondrial contamination and were suitable for studies of amino acid transport. L-Serine transport showed a clear ionic specificity, maximum incorporation being observed when an inwardly directed NaSCN gradient was used. Na(+)-dependent L-serine transport was dependent on assay temperature and membrane potential, and it seemed to be carried out by two different transport systems. An essential sulfhydryl group seemed to be involved in the transport process.

Mouse liver free amino acids during the development of Ehrlich ascites tumour

Sequential amino acid concentrations were determined in the liver of mice infested with a highly malignant strain of Ehrlich ascites tumour cells. The liver concentrations of a certain group of amino acids showed changes consistent with those previously reported for plasma, ascitic liquid and tumour cells during tumour growth. Shortly after tumour transplantation a significant decrease of the essential amino acids methionine, threonine, valine, isoleucine + phenylalanine, leucine, lysine and histidine, was detected. Some non-essential amino acids, mainly the gluconeogenic substrates alanine and serine, showed a strong reduction in hepatic concentrations during the first days; these amino acids remained significantly lower than controls until animal death. Interestingly, hepatic glutamine increased at days 1 and 2 after inoculation, and proline showed a sustained increase from the seventh day onwards, reaching a value double the control at the end of animal life.

[Monoamine concentration in the cerebrospinal fluid of patients with subarachnoid aneurysm]

Using a spectrofluorometric method, the concentration of the major monoamines, norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-), and 5-hydroxyindoleacetic (5-HIAA) was determined in cerebrospinal fluid (CSF) of patients with subarachnoid aneurysm before its rupture. DA, 5-HT, and 5-HIAA levels in CSF were found significantly increased when compared with the corresponding values found in persons with no clinical alterations of central nervous system (CNS). No significant differences were seen in NE values in CSF when data from patients with subarachnoid aneurysm were compared to their control subjects. Data obtained suggest that of NE diffusion to CSF could be at a different rate than that of the other monoamines measured. Alternatively, the reuptake of NE could vary in relation with that to the other monoamines in the affected brain tissue during the onset and development of the aneurysm. Results may also indicate a possible accumulation of NE in brain tissue adjacent to the damaged areas as a result of an increased monoaminergic activity, which, could be involved in the pathophysiology of aneurysm rupture.

Nitrogen metabolism in tumor bearing mice

In experiments with whole animals infested with a highly malignant strain of Ehrlich ascites tumor cells, serial concentrations of amino acids were determined for host plasma, ascitic fluid, and tumor cells, throughout tumor development. Concentration gradients of glutamine, asparagine, valine, leucine, isoleucine, phenylalanine, tyrosine, histidine, tryptophan, arginine, serine, methionine, and taurine from the host plasma toward the ascitic liquid were established; while on the other hand, concentration gradients from the ascitic liquid toward the plasma were established for glutamate, aspartate, glycine, alanine, proline, and threonine. With the exception of aspartate the concentrations of these amino acids were highest inside the cells. Arginine was the only amino acid not detected in tumor cells. In vitro incubations of tumor cells in the presence of glutamine and/or glucose, as the energy and nitrogen sources, confirmed the amino acid fluxes previously deduced from the observed relative concentrations of amino acids in plasma, ascitic liquid, and tumor cells, suggesting that glutamate, alanine, aspartate, glycine, and serine can be produced by tumors. These findings support that changes in amino acid patterns occurring in the host system are related to tumor development.

Altered ornithine metabolism in tumor-bearing mice

A flux of ornithine from the host tissues to the tumor was deduced from the concentrations of ornithine in plasma, ascitic liquid, liver and tumor cells during tumor growth. The activities of arginase and ornithine decarboxylase in both liver and tumor cells confirmed this proposed ornithine supply. Moreover, "in vitro" incubations of tumor cells showed that glutamine could be an additional source of ornithine for tumors. Finally, shortly before death, when tumor cell proliferation had ceased, altered hepatic ornithine metabolism was also detected.

Contribution by host tissues to circulating glutamine in mice inoculated with Ehrlich ascites tumor cells

Twenty-four h after tumor transplantation increases of free glutamine in plasma, liver, and kidney occurred simultaneously with the exponential phase of tumor growth. Kidney and muscle glutamine synthetase also increased in the first 2 days following tumor transplantation, while kidney and liver glutaminases decreased. The levels of free glutamine in plasma and tissues, and the activities of glutamine synthetase and glutaminase, tended to approach normal values in the last days of life of the tumor-transplanted animals. Eleven days after transplantation, liver glutamine synthetase activity diminished. The results are discussed in terms of a glutamate/glutamine intercellular cycle which could augment the circulating glutamine, the main source of nitrogen for tumor cells.

Gross distortion of atrioventricular and ventriculo-arterial relations associated with left juxtaposition of atrial appendages. Bizarre form of atrioventricular criss-cross

Two pathological specimens are described in which a bizarre distortion of atrioventricular and ventriculoarterial relations existed. In both cases anterior and leftward displacement of the tricuspid valve coexisted with rightward displacement of the infundibular regions and semilunar valves. Abnormal expansion of the AV canal, possibly secondary to malrotation of the cardiac tube, is considered as a possible cause of the anomaly. One of the hearts showed severe subpulmonary stenosis produced by a valve-like structure which was well differentiated, with a complete annulus and chordae tendineae that inserted in a parachute-like fashion on the infundibular septum. The morphology of this structure was clearly different from that fo the fibrous tags described in other anomalies. Its origin is uncertain. These anomalies have important implications in relation to the nomenclature and classification of congenital heart malformations, and illustrate the value of recent modifications of the segmental approach.