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J C Werner

Publications and source records attributed to J C Werner.

38 records · Page 3Linked to original sources

Biochemical correlates of dexamethasone-induced relative cardiomegaly in neonatal rats.

Dexamethasone induces a relative cardiomegaly in neonatal rats. Biochemical analyses, performed on hearts at seven days postpartum, disclosed that dexamethasone increased protein content without significantly altering DNA or RNA content. While dexamethasone decreased absolute actinomyosin and collagen content, the relative abundance of these proteins as a function of heart mass was increased and the ratio of muscle protein to collagen remained constant. In addition, dexamethasone increased glycogen but decreased fatty acid content. Thus, dexamethasone treatment of rats during the neonatal period appears to induce a relative hypertrophic cardiomyopathy complicated by fibrosis and metabolic derrangement of myocardial maturation.

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Dexamethasone-induced histopathology of neonatal rat myocardium.

Dexamethasone-induced relative cardiomegaly in neonatal rats mimics hypertrophic cardiomyopathy seen in premature infants receiving dexamethasone for bronchopulmonary dysplasia. Dexamethasone reduced cellular density by approximately 20%. However, dose related increases in mean fiber diameter were seen and mitotic index was doubled at 12.5 micrograms dexamethasone/injection. In addition, dexamethasone induced collagen accumulation throughout the myocardium in an apparently dose dependent manner. These data suggest that dexamethasone promotes (i) myocardial hypertrophy and possibly hyperplasia and (ii) fibrosis and possibly fibroplasia. Further studies are required to determine relationships between disseminated collagen deposition and other suggested metabolic changes and the observed compensatory myocardial hypertrophy and hyperplasia.

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