Histological and ultrastructural changes of cardiomyocytes in experimental rats with tail thrombosis following subplantar application of carrageenin.

OBJECTIVE: To describe histological and ultrastructural changes of cardiomyocytes in experimental rats following subplantar administration of carrageenin. MATERIAL AND METHODS: In adult rats, an acute inflammatory reaction was induced by subplantar injection of 0.1 ml of 1% sterile carrageenin solution. In a total of 10 rats, which developed gangrene of tails in 5- to 12-cm-long segments, were killed and their internal organs fixed in 10% formaldehyde solution and subsequently processed for paraffin embedding. Later, blocks of the ventricular heart tissue were refixed and reprocessed for Araldite embedding and ultrastructure observation. Similarly, the cardiac muscle of control, carrageenin-injected rats which did not develop vascular thrombosis was processed. RESULTS: The cardiomyocytes of rats injected with carrageenin showed focal dystrophic alterations, enlarged mitochondria with densely packed concentrically oriented cristae, and many dense and irregularly shaped deposits with microgranular helicoid organization. Normal cardiomyocytes were observed in control rats. Complicating thrombosis of tail blood vessels leading to extensive tail necroses were also histologically confirmed. CONCLUSION: These findings demonstrate specific pathogenic effect in the cardiovascular system of the carrageenin-treated rats.

Immunohistochemical study of the apoptotic mechanisms in the intestinal mucosa during children's coeliac disease.

Mechanisms leading to morphological changes of the small intestine during coeliac disease (CD) are not yet completely recognized; however, two main processes have been suggested recently: remodeling of mucosa by matrix metalloproteinases, and mucosal atrophy by apoptosis. The aim of this study was analysis of the expression of proteins regulating apoptosis in the small intestine of children with active CD (ACD) and potential CD (PCD). Jejunal biopsies of 43 children with PCD and untreated ACD and 21 control samples were analyzed by means of standard indirect immunohistochemical technique for Fas, Fas ligand (Fas-L), tissue transglutaminase (tTG), Bcl-2, and glutathione S-transferase (GST) expression. We found significantly lower numbers of Fas-expressing enterocytes in the ACD patients than in PCD patients and controls. Similarly, the number of Fas-positive mucosal lymphocytes was decreased in ACD when compared with PCD. The number of Fas-L- and tTG-expressing enterocytes and mucosal lymphocytes was higher in both PCD and ACD. On the other hand, the number of Bcl-2-positive mucosal lymphocytes in PCD as well as ACD was significantly lower. The expression of tTG in extracellular matrix was significantly higher in PCD and ACD when compared with controls. Our results showed that Fas and/or Fas-L, Bcl-2, and tTG may be involved in apoptotic pathways leading to mucosal atrophy in children with CD. tTG changes are in agreement with the presumed role of this protein in the pathogenesis of CD.

Heterotopic cardiomyocytes in the wall of pulmonary vessels in experimental animals.

Heterotopic cardiomyocytes (CMC) have been described in the wall of pulmonary veins including intraparenchymatous branches, in various species of laboratory animals. Brief note is given here of their morphology including electron microscopy and immunohistological findings. From the current literature hints concerning arrhythmogenic activity of heterotopic CMC in pulmonary vessels in the possible initiation of atrial tachyarrhythmia and fibrillation are also mentioned.