Biomedical subjects

E Bednarska

Publications and source records attributed to E Bednarska.

At least 19 recordsLinked to original sources

PubMed1995

Calcium in pollen-pistil interaction in Petunia hybrida Hort. II. Localization of Ca2+ ions and Ca(2+)-ATPase in unpollinated pistil.

The localization of Ca2+ and Ca(2+)-ATPase activity in the unpollinated pistil of Petunia hybrida has been studied. Free or loosely sequestered Ca2+ ions have been found: (1) in the stigma exudate, (2) in the pistil transmitting tract, (3) on the surface of ovule, (4) in the cell wall of the embryo sac. The sites of Ca2+ sequestration in the transmitting cells were the plastids and vacuoles. In some cells, the Ca2+ ions were associated with the tonoplast and plasmalemma underlying the transverse walls which connect the transmitting cells. The sites of particular accumulation of Ca2+ were the surfaces of the placenta and of the ovule. In the ovule, numerous precipitates occurred in the extended walls connecting the embryo sac with the cells of the nucellus. Ca(2+)-ATPase was commonly localized on the plasmalemma (1) of the cells of the transmitting tract of the stigma and style, (2) of the placenta and (3) of the somatic cells of the ovule. The plasmalemma of the embryo sac cells was nearly completely devoid of the reaction product.

Antimony↗

PubMed1995

Calcium in pollen-pistil interaction in Petunia hybrida Hort. III. Localization of Ca2+ ions and Ca(2+)-ATPase in pollinated pistil.

Studies were carried out of CA2+ and CA(2+)-ATPase localization in pollinated (6 and 48 h after pollination) pistils of Petunia hybrida. The results were confronted with CA2+ localization in mature pollen grain and in unpollinated pistil. It has been found that after pollination the number of CA2+ sequestered in the stigmal exudate and in the sporoderm of the pollen grain gets lower. That phenomenon was associated with the appearance of a large number of Sb/Ca precipitates in the submembrane cytoplasm of the germinating pollen. In the vacuolized pollen grain, i.e. grown into a pollen tube, there were only a few precipitates. In the pollen tube, CA2+ were found in the organelles of the tip cytoplasm and in the external pectin cell wall. Studies with the use of 45Ca2+ have revealed that the source of calcium ions incorporated into the pollen tube tip and its pectin wall is the transmitting tract of the style. In the transmitting tract overgrown with pollen tubes, Ca2+ were located in the intercellular matrix and in the transmitting cells. Sb/Ca precipitates occurred in the nuclei, around the secretory vesicles and on the plasmalemma in the transverse walls region. Elevated Ca2+ level was found in degenerating cells (inhibited pollen tubes, transmitting cells, nucellar cells). The progressing degeneration process of the cells of the transmitting tract of the pollinated pistil was associated with a decrease in the activity of plasmalemmal Ca(2+)-ATPase.

Antimony↗

PubMed1994

Calcium in pollen-pistil interaction in Petunia hybrida Hort. I. Localization of Ca2+ ions in mature pollen grain using pyroantimonate and autoradiographic methods.

The localization of Ca2+ in the mature pollen grain and the flow of these ions from the somatic tissues of the anther to the pollen grains has been studied using pyroantimonate and autoradiographic methods. In the pollen grain, Ca2+ ions have been localized in the sporoderm and in the cytoplasmic vesicles of probably dictyosomal origin. Calcium ions were transported into the sporoderm together with the compounds of degenerating tapetum. The material of degenerating tapetum forms pollen coat surrounding the mature pollen grain.

Antimony↗

PubMed1993

Localization of calcium-dependent ATPase in germinating pollen grain and pollen tube in Vicia faba.

It was demonstrated by a cytochemical method that the calcium-dependent ATPase was present in the germinating pollen grain. Immediately after hydration the enzyme was observed in the pollen plasmalemma. During germination, the chief sites of the enzyme activity were the plasmalemma around the aperture site and the cisternae of endoplasmic reticulum. In the pollen grain with a grown tube, the enzyme was localized in the plasmalemma of the tube tip, in the endoplasmic reticulum below the tip, and in the tonoplast of the vacuoles formed in the pollen grain after tube germination.

Calcium-Transporting ATPases↗

PubMed1980

Results after resection of postinfarction left ventricular aneurysms.

Although left ventricular aneurysmectomy (LVA) is a common surgical procedure, the late functional and hemodynamic results have not been well defined. This presentation describes our results with LVA in 135 patients operated between 1969 and 1979. Associated procedures were performed in 57 (42%) including coronary bypass grafting in 50, valve replacement in 5, closure of ventricular septal defect in 2, or combinations of these in 3 patients. One hundred four of the 122 hospital survivors were followed from 2 to 107 months (mean = 37 months). There were 13 hospital deaths (9.6%), 12 late deaths (9.8%) and an actuarial 5-year survival rate of 77%. Clinical improvement of preoperative heart failure occurred in 82%, and of angina in 70%. Only 33 patients (30%) returned to normal work. Bicycle exercise testing in 70 patients showed normal working capacity in 41 (59%). Recatheterization in 49 patients showed no significant changes in left ventricular end-diastolic pressure or cardiac index, and a borderline reduction of the total ejection fraction. Ventricular arrhythmias were detected by long-term ECG in 70% of all patients after surgery. Of those with preoperative life-threatening arrhythmias, rhythm improvement was noted in 50%, but only 2 of 13 patients were free of arrhythmias after operation. This study demonstrates a greater frequency of postoperative symptomatic and functional improvement as compared to hemodynamic and ECG improvement. Ventricular tachyarrhythmias originating from post-infarct scars increased intra- and postoperative risk and aneurysmectomy alone is considered insufficient for treatment of these disturbances. Further electrophysiologic investigations are needed and additional surgical measures may be necessary to improve the subset of patients with life-threatening arrhythmias.

Adult↗

PubMed1975