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Biomedical subjects

J Andres

Publications and source records attributed to J Andres.

62 records · Page 4Linked to original sources
PubMed1983

[An early childhood erythrocyte phospholipid distribution as further indication of persistence of neonatal erythrocyte characteristics in Diamond-Blackfan anemia].

Comparisons of erythrocyte and plasma phospholipids made among adults, newborns, and a female patient with Diamond-Blackfan anaemia (DBA) revealed some indications for the continual existence of a neonatal phospholipid distribution in DBA. The relative percentage of phospholipids in erythrocytes and plasma were similar in newborns and in the female patient. The other peculiarities characteristic of newborns, such as deviations in the absolute phospholipid content, typical fatty acid patterns of phospholipids, could not be identified in DBA.

Adult↗
PubMed1981

Effects of experimental volume-overload hypertrophy on myocardial blood flow and cardiac function.

To examine the effects of volume-overload hypertrophy on regional myocardial perfusion, we determined myocardial blood flows with microspheres at rest, during exercise, and during exercise with adenosine infusion in dogs with aortocaval fistulas for 12 wk (group 2) and sham-operated controls (group 1). A subgroup of six animals (group 3) was studied both before and after shunt closure in order to separate the influences of hypertrophy from the hemodynamic effects of the fistula. Epicardial blood flows in animals with patent fistulas were significantly greater than in controls under all conditions (P less than 0.05). However, endocardial blood flows were lower at maximal exercise and with adenosine, so that the endocardial-to-epicardial blood flow ratios were reduced 36 and 28%, respectively(P less than 0.05). These flow abnormalities were reversed by closing the fistula prior to regression of hypertrophy. Moreover, coronary resistance per unit of myocardium was not different for the three groups. These results suggest that the blood-flow abnormalities seen in the exercising dog with an aortocaval fistula are secondary to hemodynamic considerations and not to hypertrophy itself. Low aortic diastolic pressures and high myocardial oxygen demands during exercise may combine to produce subendocardial hypoperfusion in this model.

Animals↗
PubMedDate not supplied

Contractile proteins in globally "stunned" rabbit myocardium.

The isolated working rabbit heart preparation was used to study whether the "contractile machinery" remains unchanged in globally stunned myocardium. The function of the heart has been measured in nonischemic and postischemic conditions. The effect of isoprenaline or calcium chloride administration in both conditions was also studied. Myocardial contractile function was significantly depressed after 20-min global ischemia and returned to normal after CaCl2 and supranormal values after isoprenaline administration. From hearts used in experiments myofibrils were prepared and their ATPase activity was determined. It was observed that myofibrils prepared from "stunned" myocardium showed about 50% increase in ATPase activity in the presence of CaCl2. Subjection of the heart to ischemia caused a decrease in calcium sensitivity of the myofibrillar ATPase. Myofibrils obtained from ischemic hearts but subjected to isoprenaline or CaCl2 administration exhibited increased calcium sensitivity over that of control heart. These effects were accompanied by changes in the extent of phosphorylation of troponin I (TNI) and myosin light chains. The modification of contractile apparatus in the postischemic period described in this paper may contribute to the overall mechanism of myocardial stunning.

Adenosine Triphosphatases↗