Thrombocythemia and thrombosis of the adrenal vessels.

The authors describe a case of primary thrombocythemia and thrombosis of the adrenal vessels which they were able to examine by arteriography of the renal and adrenal arteries, by adrenal CT and at autopsy following the patient's death. The available research data and hypotheses concerning the pathogenesis of thrombosis and hemorrhage in thrombocythemia are reviewed, but the relationship between platelet number and function and the incidence of thrombotic and hemorrhagic complications has not yet been clearly established. Pathogenesis of thrombosis and hemorrhage in suprarenal vessels is not clear and the majority of authors postulate early venous damage.

S-adenosylmethionine inhibits collagen synthesis by human fibroblasts in vitro.

Previous studies have indicated that S-adenosylmethionine (SAMe), the precursor of methyl groups and thiols, exerts an anti-inflammatory activity. In order to clarify whether this molecule also has antifibrotic properties, we evaluated its pharmacological effects on human fibroblasts in vitro. Accordingly, fibroblasts between 5 and 10 subcultures were incubated for 24 h with different SAMe concentrations (from 0.005 to 626 microM). Fibroblast proliferation measured by incorporation of labeled thymidine was not affected by SAMe in the range of the tested concentrations. Moreover, cell viability assessed by trypan-blue exclusion test was greater than 98% in all cultures, without any difference between SAMe and control cultures. Collagen synthesis estimated by HPLC measurement of hydroxyproline in both media and cells was not modified by SAMe concentrations lower than 0.05 microM. On the other hand, SAMe concentrations higher than 0.05 microM significantly (p less than 0.01) reduced collagen synthesis as compared with untreated controls. This effect was not dose-dependent. In conclusion, this study indicates that SAMe addition to fibroblasts in the range of concentrations which can be found in vivo induces a marked decrease (about 50% of control value) in collagen synthesis with no adverse effects on cell proliferation and viability. These findings suggest further investigation of the potential antifibrotic role of SAMe.

[Atrial dissociation in complete intra-atrial block]. / Dissociazione atriale da blocco intra-atriale completo.

Atrial dissociation due to a complete intraatrial block is a very rare electrocardiographic occurrence. Two cases of this atrial arrhythmia characterized by two atrial ectopic beats of different origin are reported. The electrophysiologic mechanisms of the arrhythmia are discussed briefly.