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Biomedical subjects

A Losada

Publications and source records attributed to A Losada.

At least 55 records · Page 3Linked to original sources
PubMed1996

Autosomal location of a new subtype of 1.688 satellite DNA of Drosophila melanogaster.

During the screening of a Drosophila melanogaster YAC library with DNA from the minichromosome Dp(1;f)1187 we isolated a clone, yw20D5, which contains a new subtype of 1.688 satellite DNA. Although the sequences of several monomers subcloned from the YAC show a considerable variation in length, the derived consensus sequence is 356-bp long. This new subtype and the one constituted by the 353-bp repeats are both located on the left arm heterochromatin of chromosome 3, arranged in separate arrays. Despite their autosomal location, phylogenetic relationships among 1.688 satellite sequences suggest that they may have originated from the 359-bp repeats of the X chromosome heterochromatin. We have used the new 356-bp repeats to investigate whether sequences related to the 1.688 satellite are dispersed along the euchromatic arms of the autosomes in a similar way to that in which they are found along the X chromosome euchromatin.

Animals↗
PubMed1996

[Cardiac angiosarcoma].

We report a case of a 29-year-old patient with recurrent hemorrhagic pericardial effusion secondary to a right atrial mass detected by transthoracic echocardiography. A more detailed anatomic study was provided by transesophageal echocardiogram and nuclear magnetic resonance imaging. During surgery, a biopsy confirmed the diagnosis of angiosarcoma. We discuss the contribution of echocardiography and other noninvasive methods to evaluate intracardiac tumors. A brief review of treatment and prognosis is made.

Adult↗
PubMed1996

[Persistence of the left superior vena cava associated with aortic insufficiency: diagnostic and therapeutic considerations].

In the course of the routine evaluation of a 26-years-old male for acquired aortic valve disease the persistence of a left superior vena cava draining into the coronary sinus was detected. This is a frequent congenital malformation of the systemic venous system that has no hemodynamic consequences in itself, though it may be associated to other congenital or acquired cardiac malformations that may require surgery. The preoperatory detection of the anomaly prevents unexpected problems when connecting the cardiopulmonary bypass. We emphasize the importance of procedures that suggest the diagnosis and characterize the anatomo-functional nature of the condition--including transthoracic and transesophageal echocardiography using echocardiographic contrast, and cardiac catheterization with cardiac and vascular angiography.

Adult↗
PubMed1995

[Hypertrophic myocardiopathy and ostium primum].

A 45-year-old male with palpitations and a heart murmur was investigated. Echocardiography and haemodynamic study revealed the presence of a ostium primum type interatrial communication with left-right shunting and asymmetric hypertrophic heart disease. There was no subaortic obstruction, but anterior systolic movement of the mitral valve was detected that did not contact with the interventricular septum--in part due to the paradoxical motion of the latter. The possible benefit of surgery in this infrequent association is discussed, and a review is made of the literature.

Cardiac Catheterization↗
PubMed1993

[Left ventricular outflow obstruction due to accessory mitral tissue].

An asymptomatic 31-year-old woman was studied because she presented a systolic ejection cardiac murmur. The echocardiogram showed a mobile, sac-like mass attached to the ventricular surface of the anterior mitral leaflet and its chordae tendineae and papillary muscle. This structure moved to the left ventricular outflow tract during every systole occupying the subaortic area. Conventional and color-coded Doppler examination revealed left ventricular outflow obstruction caused by the accessory mitral valve tissue that produced a high-velocity turbulent flow pattern in the subaortic area where the sac-like structure approximated to the outflow tract walls.

Adult↗
PubMed1992

[Fetal cardiac arrhythmia characterized by Doppler echocardiography].

A fetal arrhythmia was detected in a pregnant woman. Fetal Doppler-echocardiography did not reveal cardiac structural alterations; the Doppler flow velocity recordings at the level of the left ventricular outflow tract revealed the continuous succession of three cardiac cycles: a prolonged cycle (456 +/- 6 ms, mean of five measurements), a medium duration cycle (428 +/- 4 ms) and a short cycle (296 +/- 4 ms) after which the prolonged cycle repeated. Identification of the late ventricle filling phase of the atrial systole in the Doppler flow velocity waveform during the long and medium duration cycles, the detection of the systolic movement of the atrial walls preceding contraction of the ventricle walls during the shortest cycle and the verification that summation of the shortest and longest cycles was inferior to twice the intervening cycle, supported the idea that the arrhythmia was produced by frequent atrial premature contractions (one every two sinus beats). The fetal arrhythmia progressively disappeared during pregnancy until delivery without complications, and the newborn's ECG only revealed sporadic premature atrial contractions.

Adult↗
PubMed1991

Large-volume paracentesis and intravenous saline: effects on the renin-angiotensin system.

Fourteen cirrhotic patients with tense ascites were treated with total paracentesis and intravenous isotonic saline infusion. Standard liver and kidney function tests, plasma renin activity and aldosterone concentration were measured before, at 48 hrs and at 7 days after total paracentesis. The volume of ascites removed was 7.7 +/- 5.6 l (mean +/- S.E.M.). None of the treated patients had clinical complications or significant alterations in liver or kidney function test results. Paracentesis and intravenous isotonic saline infusion were not associated with significant changes in mean plasma renin activity or plasma aldosterone concentration. These results suggest that this therapeutic procedure could be a safe and cost-effective alternative treatment of tense ascites in patients with cirrhosis.

Aged↗
PubMed1990

[Dowling-Degos disease].

We report two cases of Dowling-Degos' disease, one affecting the vulvovaginal semimucose, and one associated to a terminal malignant neoplasia. We remark the importance of this knowledge in order to distinguish it from malignant acanthosis nigricans or other patterns of melanosis or lentiginosis when located within mucose or semimucose, specially at the genitals. All cases associated to malignant neoplasia described are emphasized. However Dowling-Degos' disease is considered to be a nonparaneoplasic genodermatoses, this association should be taken into account.

Aged↗
PubMed1975

Signal input for a chemotactic response in the cellular slime mold Dictyostelium discoideum.

Drops with different concentrations of 3':5'-cyclic AMP were deposited at various distances from small populations of Dictyostelium discoideum amoebae, and the distances over which 50% of the amoebae drops reacted positively were determined. The linear regression analysis of a bouble logarithmic plot of distance against concentration gives a straight line with a slope of 1/4.25, which value suggests that the amoebae respond to a spatial gradient of cyclic AMP concentration. The threshold value for the signal is 3.6 X 10(-9) M/mm with a sensitivity of measurement of about 1%. These findings are discussed in relation to our present knowledge of cyclic AMP receptors.

Chemotaxis↗