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Biomedical subjects

A Nava

Publications and source records attributed to A Nava.

196 records · Page 11Linked to original sources
PubMedDate not supplied

[Electro-vectorcardiographic analysis of the negative, diphasic and bifid T wave in right precordial leads in young subjects].

Morphology, genesis and incidence of isolated T wave abnormalities on right precordial leads of healthy young individuals were studied in this work. ECG were obtained from 1510 healthy subjects aged 14 to 40 years consecutively submitted to a cardiological evaluation in order to assess their fitness for sport. In 510 of them a VCG was made too. The results showed that T waves were rarely negative beyond V1 (0.46%) and even more rarely negative from V1 to V3 (0.13%); diphasic T waves were present in 2.38% and bifid T waves in 6.15% of our cases. The T loop of VCG tended to be more posteriorly displaced and evolved from a counterclockwise to a clockwise rotation as the presence of negative T waves spread toward left on precordial leads. The "+-" type of diphasic T wave corresponded to a counterclockwise rotation of the T loop, the "-+" type to a clockwise rotation. Bifid T waves were associated with figure of eight or "arched" T loops of VCG. The T loops of those subjects who underwent a second evaluation after several years tended to be displaced more anteriorly, with counterclockwise rotation. The causes of these T wave abnormalities have not been clearly explained yet, even if a slight delay in the right final vectors was present in the majority of our cases.

Adolescent↗
PubMedDate not supplied

Modulation of receptor levels in canine breast tumors by administration of tamoxifen and etretinate either alone or in combination.

Steroid receptors were measured in a series of 30 operable canine mammary gland tumors; both cytoplasmic estrogen (ERc) and progesterone (PgRc) receptor mean concentrations were very low with respect to the mean levels found in humans. Therefore a study was designed to modulate receptor levels by administration of Tamoxifen and Etretinate, either alone or in combination. Forty dogs with resectable, histologically documented mammary gland tumors were subdivided into the following treatment groups: a. Etretinate (1 mg/kg/d) p.o. for 7 days followed by Tamoxifen (0.7 mg/kg/d) p.o. for 7 days; b. Tamoxifen (0.7 mg/kg/d) p.o. for 14 days; c. Etretinate (1 mg/kg/d) p.o. for 14 days; d. 14 days placebo, and cytoplasmic ERc and PgRc and nuclear ER (ERn) were measured before and after the treatment. An increase of ERc and ERn was observed after administration of Tamoxifen, while an increase of ERc only was seen after treatment with Etretinate. We conclude that canine mammary tumors are indeed hormone sensitive despite their very low receptor concentrations and a suitable treatment can in fact modulate receptor levels. However, further studies are needed better to define the optimal treatment regimen in order to achieve maximal steroid receptor induction.

Animals↗
PubMedDate not supplied

[Electro-vectorcardiographic behavior of right bundle branch block in endocardial cushion defects. Its probable relation to the so-called left anterior fascicular hemiblock].

We have investigated the possible ECG signs of incomplete Left Anterior Hemiblock (LAH). As an experimental model we chose the endocardial cushion defect, which is proved to have a ventricular activation correspondent to different degrees of LAH due to the particular disposition of the AV node and the His bundle. The VCG of 50 patients with endocardial cushion defect were divided into 5 groups according to the entity of the left and superior deviation of the maximum left vector. Comparison with the ECG signs shows that: a) minimal degrees of LAH occur with simple counterclockwise rotation of the frontal loop without a significant left axis deviation; b) there is no linear correlation between the importance of the left axis deviation and the signs of left ventricular activation asincronism. We conclude that, with the exception of this particular congenital heart disease, minimal LAH degrees can only be suspected on the basis of a counterclockwise VCG frontal loop, because the ECG diagnosis is possible only when the left axis deviation becomes important.

Adolescent↗
PubMedDate not supplied

Antiphospholipid syndrome in patients with cyanotic congenital heart disease.

Patients with cyanotic congenital heart disease exhibit an increased incidence of thrombotic episodes and are frequently thrombocytopenic. We studied the sera of 15 patients with this type of heart malformation, searching for anticardiolipin antibodies. 3/15 had positive results. The three of them were adult females; two had thrombotic episodes and a false positive VDRL. Thus, cyanotic congenital heart disease may be another disease entity associated with the antiphospholipid syndrome.

Adult↗
PubMedDate not supplied

The conduction system in corrected transposition with situs inversus.

The location and course of the conduction system were investigated by serial section in two hearts with corrected transposition of the great arteries in situs inversus. In the first case, characterized by dextrocardia, the interventricular septum was intact, while in the second case with levocardia, a high ventricular septal defect was associated with pulmonary atresia. In both hearts, a regular posterior connecting AV node was present, left-sided in one case and right-sided in the other. The bundle branches were distributed in the morphologically appropriate ventricles. Extensive hemorrhage and coagulation necrosis of the common bundle and bundle branches were observed in the first case, being consequent upon surgical replacement of the right-sided tricuspid valve. The common bundle ran below the membranous septum in this case. In the heart with ventricular septal defect it was related to the postero-inferior rim of the defect. In both cases, an accessory AV node was located anteriorly in the interatrial septum but did not connect with the ventricular musculature. The different position of the atrioventricular conducting tissue in corrected transposition, between cases in situs solitus and situs inversus, is emphasized.

Atrioventricular Node↗