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Biomedical subjects

M Kopacz

Publications and source records attributed to M Kopacz.

6 recordsLinked to original sources
PubMed1993

Reperfusion arrhythmias and purine wash-out in isolated rat and rabbit heart. Effect of allopurinol, dimethylthiourea and calcium reduction.

The effects of perfusate calcium reduction, allopurinol and dimethylthiourea on reperfusion-induced arrhythmias and purine wash-out in isolated rabbit and rat hearts were compared. The overall incidence of reperfusion-induced ventricular tachycardia (VT) was 88% and 94% and that of ventricular fibrillation (VF) was 44% and 88% in the control rabbit and rat hearts, respectively. VF was reduced to 10% and 0% in rat and rabbit hearts subjected to perfusate calcium reduction (0.4 mM for 1 min before ischemia and for 1 min before and throughout reperfusion), respectively. In allopurinol, 1 mM, perfused rat hearts the overall incidence of VF was not changed and only the incidence of a sustained VF (that lasting for at least 10 min) was reduced. VT and VF were prevented in allopurinol-perfused rabbit hearts. Dimethylthiourea, 10 mM, reduced the incidence of VF in rat hearts to 16% and did not significantly affect VT and VF in rabbit hearts. In untreated rat hearts, the major purine compounds washed out upon reperfusion were inosine, hypoxanthine, xanthine and urate. Allopurinol augmented the wash-out of adenosine and abolished that of xanthine and urate. In untreated rabbit hearts, the major purine washed out were inosine, adenosine and hypoxanthine. Allopurinol did not cause further increase in adenosine wash-out in rabbit hearts. We speculate that: (1) calcium mediated arrhythmogenic mechanism is operating both in reperfused rat and rabbit heart; (2) free radical mediated mechanism is of an importance only in rat heart; (3) neither a decreased free radical production secondary to xanthine oxidase inhibition nor the augmentation of adenosine wash-out is a likely explanation for the antiarrhythmic effect of allopurinol in reperfused hearts; and (4) high level of myocardial adenosine accumulation during ischemia, probably secondary to low xanthine oxidase activity, may play a role of a natural defence mechanism in ischemic/reperfused rabbit heart.

Adenosine↗
PubMed1977

Pulmonary resection.

Seventy-seven patients who had elective pulmonary resections were enrolled in a prospective double-blind study to assess the role of prophylactic antibiotics in preventing postoperative infections. Criteria for infection were strictly defined. A five-day course of a cephalosporin (2 gm/day in divided doses) was compared to an identical placebo. There were 17 infections in the 34 patients in the placebo group (50%), compared to only eight infections in the 43 patients in the antibiotic group (19%) (P = .005). When infections unrelated to thoracotomy and minor infections were excluded, the advantage of prophylactic antibiotics proved even more evident. Fourteen thoracic infections occurred in the placebo group (41%) compared to only two thoracic infections (4.7%) in the antibiotic group (P = .0002). No relationship of infection rate to the extent of pulmonary resection was found. A history of smoking, the presence or absence of chronic bronchitis, spirometric abnormalities, and obesity were all analyzed; none was related to the development of infection. We conclude that the routine use of perioperative antibiotics is indicated to prevent postoperative infections in pulmonary resection.

Abscess↗
PubMedDate not supplied

The influence of sulfonated bioflavonoids on enzymatic oxidation of arachidonic acid and on non-enzymatic lipid oxidation.

Sulfonic acids of quercetin and morin as well as their ferrous and cupric complexes were synthetized and investigated. Sulfonic derivatives of quercetin were much weaker inhibitors of soybean lipoxygenase than quercetin itself. Morin and its derivatives were inactive. Antioxidant properties of quercetin derivatives were in the same range as for quercetin. Most of the investigated compounds stimulate cyclooxygenase when 100 microM of arachidonic acid is used as a substrate. Ferrous complex of quercetin 5'-sulfonic acid was an inhibitor of this enzyme.

Antioxidants↗