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Biomedical subjects

G Alonso

Publications and source records attributed to G Alonso.

At least 163 records · Page 9Linked to original sources
PubMed1978

Cytostatic quinones. 3. Synthesis of benzotriazolequinones by a new oxidation with m-chloroperbenzoic acid. Biochemical studies.

Oxidation of N-1 and N-2 alkylbenzotriazoles with m-chloroperbenzoic acid afforded 1-alkylbenzotriazole 3-oxides and 2-alkylbenzotriazole-4,4-diones, respectively. The quinonic compounds inhibited the "in vitro" growth of both HeLa and KB cells, the synthesis of macromolecules (DNA, RNA, and proteins), and the uptake of glucose by Ehrlich carcinoma ascites cells. A possible mode of action is suggested.

Animals↗
PubMed1978

[Monoaminergic and peptidergic innervation of rat median eminence, studied by a combination, in the same hypothalamus, of histofluorescent, immunocytochemical and radioautographic technics].

The application of a combined histofluorescence-immunocytochemical and radioautographic technique on the same rat hypothalamus has revealed : 1) a close correlation between the dopaminergic fibers and LH-RH containing axons all along the external layers of the ME, 2) a probable origin within the periventricular hypothalamus of some of the SRIF containing axons evidenced in the external zone of the ME, 3) the exclusive location within the internal ME of the axons originating within the supraoptic nuclei, 4) the ending within the external ME of the axons originating within the medial paraventricular nuclei.

Amines↗
PubMed1977

Demonstration of different glycosylated antigens in C-type virus-transformed and infected rat cells by antiserum to murine leukemia virus.

[3H]Glucosamine labeling of untransformed cells, C-type virus-transformed cells, and virus-infected cells and subsequent analysis by polyacrylamide gel electrophoresis and fluorography permitted the detection of a Pronase-sensitive macromolecular labeling that appeared in about eight regions of radioactivity in every case. Reactions of cell extracts with antiserum to Tween-ether-disrupted purified murine leukemia virus revealed, in most transformed cells, two components with a mobility of about 100,000 daltons, whereas C-type virus-infected cells revealed their radioactivity mainly in a region nearer to that of the major viral glycoprotein at about 69,000 daltons. No comparable components were apparent from the reaction of transformed or infected extracts with preimmune serum or from the reaction of untransformed uninfected cells and immune serum.

Antibodies, Viral↗
PubMed1977

HLA antigens in Forestier's disease, ankylosing spondylitis, and polyarthrosis of the hands.

HLA antigens were studied in three different groups of 50 patients each. These included (a) Forestier's disease, (b) ankylosing spondylitis, and (c) polyarthrosis of the hands. HLA typing included 12 specificities from locus A and 15 from locus B, the frequencies being compared to those in 700 normal controls. No significant differences were found in the frequency of distribution between the polyarthrosis patients and the normal population. In patients with Forestier's disease, B5 was increased, but this was not a significant difference. The antigen B27 was present in 94 per cent of patients with ankylosing spondylitis, confirming previous studies.

Adolescent↗
PubMed1976

Radioautographic study of in vivo incorporation of 3H-monoamines in the cat caudate nucleus: identification of serotoninergic fibers.

The localization of radioactivity was examined in the caudate nucleus of the cat, treated with an MAO inhibitor, following local superfusion of the ventricular surface of the structure with low concentration of 3H-catecholamines or [3H]5-HT. The caudate nucleus was superfused continuously from 30 to 240 min using a cup technique. Light microscope or high resolution radioautographs revealed: (1) a rather diffuse incorporation of 3H-catecholamines under the subependymal region which could be hardly attributed to a specific population of nerve terminals. A loose binding of 3H-catecholamines into dopaminergic terminals could be involved in this effect. (2) An intense and selective uptake of [3H]5-HT in fine scarce varicose nerve fibers localized in the ventricle as in the subependymal layer and in the neuropil of the nucleus. The labeled fibers contained numerous round or elongated large granular vesicles of 80-120 nm and exhibited only very few synaptic contacts suggesting a possible extrasynaptic liberation of 5-HT.

Animals↗
PubMed1976

Inhibitors of protein synthesis in eukarytic cells. Comparative effects of some amaryllidaceae alkaloids.

The effects of eighteen compounds obtained from bulbs of the Amaryllidaceae family were tested on (a) animal cell growth, (b) DNA, RNA and protein synthesis by intact cells and (c) protein synthesis in cell-free systems. Dihydrolycorine, haemanthamine, lycorine, narciclasine, pretazettine and pseudolycorine halted HeLa cell growth at 10(-1) mM or lower concentrations. These compounds at their growth inhibitory concentrations block protein synthesis in ascites cells and stabilize HeLa cell polysomes in vivo. Endomyocarditis virus RNA-directed cell-free polypeptide synthesis by an ascites S-30 extract and acetyl-[14C]leucyl-puromycin formation by ascites ribosomes are also inhibited by the six compounds indicated above. It is therefore concluded that they halt protein synthesis in eukaryotic cells by inhibiting the peptide bone formation step.

Alkaloids↗
PubMed1975

Cholera toxin effects on cell growth accompanied by selective alterations in metabolite uptake and modification of cell surface proteins.

Exposure of Chinese hamster ovary cells to cholera toxin at or below mug levels causes a marked morphological changes and increased adhesion and orientation of the cells. Such changes are paralleled by alterations in surface proteins as indicated by the cholera toxin-mediated modifications detectable by lactoperoxidase-catalyzed radioiodination of outer proteins. Mild tryptic treatment of cells prelabeled with [3H]glucosamine revealed a different kinetics of release of external glycoproteins in cells exposed to the toxin. An alteration in a specific glycoprotein species in cholera toxin-treated cells became evident by polyacrylamide gel electrophoresis followed by fluorography of 3H-labeled cellular glycoproteins. The effects of cholera toxin on surface proteins and growth of the cells occurred in the absence of a modification in amino acid uptake or incorporation of precursors into protein. However, thymidine uptake and glucosamine incorporation were inversely affected to toxin treatment. Some of the effects of the toxin appeared to be antagonized by colchicine.

Amino Acids↗
PubMed1975

Turnover of high-molecular-weight cell surface proteins during growth and expression of malignant transformation.

The turnover of cell surface proteins in normal rat kidney cells transformed by a temperature-sensitive Rous sarcoma virus has been studied by polyacrylamide gel electrophoresis and autoradiography using cell monolayers prelabeled by lactoperoxidase-catalyzed radioiodination. Labeling of serum-starved cells under conditions that are nonpermissive for the expression of transformation reveals most of the radioactivity in the 250,000 molecular weight region. Parallel labeling of cells simultaneously exposed to serum limitation, under conditions that are permissive for the expression of transformation, reveals some radioactivity in the same slow-migrating region, but most of the label appears in the two faster migrating regions. The relative turnover of such external proteins has been investigated by examining the relative alterations in iodinated proteins after addition of normal levels of serum to a medium of serum-starved cells. There is a greater relative turnover of the high-molecular-weight external component under conditions in which ther transformation phenotype is expressed, as compared with conditions that limit the expression of transformation.

Animals↗