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Biomedical subjects

J Ramos

Publications and source records attributed to J Ramos.

At least 181 records · Page 10Linked to original sources
PubMed1984

[Congenital vascular tumor of the larynx: cellular hemangioma].

A 9 year old child was operated upon for a very vascular tumor of the right piriform sinus, signs of which had been present at birth. Histopathologic and ultrastructural examinations showed the lesion to be composed of both endothelial and pericytic elements, suggesting the diagnosis of a cellular hemangioma. This tumoral variety, particularly rare in the larynx, has been distinguished from the group of hemangiopericytomas described by Stout and Murray, not only by its usual congenital character and course but also by its specific structure.

Child↗
PubMed1983

Diagnosis by ultrasonography and isotopic phlebography of a malformation of the inferior vena cava: proximal transposition with anterior crossing over the aorta.

A case of a previously undescribed malformation of the inferior vena cava is reported: there was distal normoposition and proximal transposition, with anterior crossing over the aorta; the right renal vein flowed into the inferior vena cava located on the left, after crossing over the anterior face of the aorta. This anomaly was shown by echography and isotopic phlebography.

Adult↗
PubMed1983

Effect of histrionicotoxin on ion channels in synaptic and conducting membranes of electroplax of Electrophorus electricus.

Histrionicotoxin (HTX) at low concentrations of 5-10 microM blocks the postsynaptic potential of the electroplax of Electrophorus electricus. At 100-fold higher concentrations, HTX blocks the directly evoked action potentials of the conducting membrane. The pH dependence of the blockade by HTX at synaptic channels is different from that at the conducting membrane. At the synapse HTX is more potent at acid pH, while at the conducting membrane it is more potent at basic pH. HTX at high concentrations antagonizes the effects of batrachotoxin, indicative of an effect on the batrachotoxin-sensitive sodium channels involved in action potential generation. While the effects of HTX on the synaptic channels are concentration, time, and pH dependent, the effects on the channels of the conducting membrane are, in addition, use dependent, suggesting interactions of HTX with the activated forms of these channels.

Amphibian Venoms↗
PubMed1983

[Carcinoid tumor of the larynx. Ultrastructural and immunofluorescence study].

Report of a 54 year-old man with a carcinoid tumor in the larynx and cervical lymph node metastasis. This left sided and dum-bell shaped tumor was spreading from the vocal cord to the piriform sinus. It was smooth, reddish and rubbery. Microscopic study showed, near by the mucosa, the tumor cells arranged in a trabecular pattern, but more disseminated and infiltrating in the deepness. Grimelius stain was positive, Masson Fontana stain negative. Electron microscopy showed neuro-secretory type granules. Immuno-histo-chemical study revealed irregularly scattered cells which were positive for ACTH, but negative for somatostatin, calcitonin and gastrin. Review of literature for this extremely rare tumor.

Carcinoid Tumor↗
PubMed1977

Fatty acid synthetase complex from the insect Ceratitis capitata.

Fatty acid synthesis capacity of the insect Ceratitis capitata has been investigated in vitro from [1-14C]acetyl-CoA using homogenates at different stages of development. A maximum activity was observed after 5--6 days of larval development. But homogenates of the pharate adult insect did not show synthetic capacity of fatty acids. Fatty acid synthetase complex has been isolated from the particle-free supernatant fraction of homogenates from the 6-day C. capitata larvae. The enzyme complex was purified 182-fold with respect to the protein contained in the crude extract. The complex was homogeneous when analysed by gel filtration and by polyacrylamide-gel electrophoresis. The molecular weight was 5.2X10(5). The enzyme was dissociated into half-molecular subunits. Amino acid analysis, general properties, stability and kinetic constants (V and Km) for the substrates are reported. The fatty acid synthetase complex from the insect contains 42+/-1-SH residues and one phosphopatetheine moiety per 5.2X10(5). Activity was dependent on the presence of NADPH; FMN strongly inhibited the enzyme activity promoted by NADPH. The enzyme complex synthesized a range of fatty acid (10:0--18:0), palmitate being the predominant end product. The proportions of fatty acids synthesized varied with substrate concentrations. Fatty acids released from the complex were almost completely in the free form.

Amino Acids↗
PubMed1970

Roadrunners: activity of captive individuals.

Two roadrunners, Geococcyx californianus, readily accepted an activity wheel as an outlet for locomotor activity. The birds were strictly diurnal and tended to be most active per unit of time in the predusk hours. There was less activity on partly overcast days than on clear days. Dim light and darkness were strongly inhibitory, even during daytime hours; bright light was stimulatory, even during nighttime hours. These findings appear to open the way for quantitative comparative studies of the influences of environmental factors on the activity of cursorial birds.

Animals↗