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Biomedical subjects

A Ramírez

Publications and source records attributed to A Ramírez.

At least 109 records · Page 6Linked to original sources
PubMed1986

[Autoantibodies in vitiligo. Clinical significance].

The occurrence of circulating autoantibodies was determined by indirect immunofluorescence in patients with vitiligo. In addition we determined the existence of anti-melanocytic antibodies by an immunofluorescence complement fixation technique, immunoglobulins in achromic and perilesional skin, complement (C3 and C4) and immunoglobulins in serum by immunoelectrophoresis. The results only indicate that a significant occurrence of circulating autoantibodies exists, especially antithyroid autoantibodies, which, moreover, are related to the vitiligos which affect important areas of the cutaneous surface (generalized vitiligo).

Autoantibodies↗
PubMed1985

Experimental and natural infection of Simulium sanchezi by Mansonella ozzardi in the Middle Orinoco region of Venezuela.

Experimental and natural infections of Simulium sanchezi by Mansonella ozzardi were studied in the area of Síquita, Territorio Federal Amazonas, Venezuela. The microfilariae developed synchronously in the blackflies, reaching stage L3 in seven to eight days at temperatures between 23 degrees and 27 degrees C. Larvae in different stages of development, including infective forms, were found in 0.6% of 662 unfed wild-caught females. These results confirm that simuliids are the main vectors of M. ozzardi in the American continent.

Animals↗
PubMed1984

Kinetic behaviour and regulatory properties of phosphofructokinase in rat bone marrow cells.

Phosphofructokinase from bone marrow cells shows sigmoidal kinetics with respect to fructose-6-phosphate when studied at near physiological concentrations of ATP (1.5 mM) and pH (7.1). The enzyme is clearly inhibited by ATP concentrations higher than 0.75 mM. pH increases maximum velocity and affinity of the enzyme towards fructose-6-phosphate and decreases the cooperative behavior of the enzyme. Citrate behaves as a negative allosteric effector. ATP deinhibition and activation of bone marrow phosphofructokinase, by either AMP or cAMP, were also observed. cAMP seems to have a higher affinity for the enzyme than AMP. cGMP does not show any antagonistic effect versus cAMP as has been previously observed in rat erythrocytes or reticulocytes.

Adenosine Triphosphate↗
PubMed1981

Effect of minoxidil on sympathetic nervous activity in clonidine-treated hypertensive patients.

The effects of clonidine and minoxidil on sympathetic nervous activity has been studied in 10 patients with accelerated or resistant hypertension. Clonidine 150 to 900 micrograms/day caused a significant decrease in blood pressure of 18.6 mm Hg, of heart rate 16.4 beats/min, of plasma renin activity 1.13ng/ml h, and of urinary noradrenaline excretion 11.55 micrograms/day, and a significant lengthening of the pre-injection period of 12.4 ms. Minoxidil 5 to 22.5 micrograms/day caused a further significant decrease in blood pressure of 24.2 mm Hg, and significant increases in heart rate 8.2 beats/min, plasma renin activity 1.68 ng/ml h and of urinary noradrenaline excretion 5.0 micrograms/day, and a significant shortening of the pre-ejection period of 20.6 ms. Neither clonidine nor minoxidil altered plasma dopamine beta-hydroxylase activity or the cardiovascular responses to treadmill exercise. It is concluded that clonidine is a useful alternative agent to block a minoxidil-induced increase in sympathetic nervous activity.

Adult↗