Dietary polyamines promote the growth of azoxymethane-induced aberrant crypt foci in rat colon

We have examined whether dietary polyamines influence the formation and initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rat colon. Effects of a combination of dietary polyamines at three dose levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g; spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied in animals in two different experimental situations: animals treated with AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a specific inhibitor of endogenous polyamine synthesis. In both experimental situations, dietary polyamines enhanced the growth of ACF, expressed as the number of large ACF (foci with three or more aberrant crypts, ACF > or = 3), whereas the formation of ACF, expressed as the number of ACF, was apparently not altered. In animals treated with AOM alone, maximal growth enhancing effect on ACF was nearly obtained with the median level of dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of DFMO was counteracted by dietary polyamines in a dose- dependent manner, and it was abolished at the highest level of polyamines. In conclusion, it was demonstrated that dietary polyamines are able to enhance the growth of AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused inhibition of ACF growth, probably by compensating for the DFMO-reduced endogenous polyamine synthesis.      

Receptors for the epidermal growth factor and estrogens in primary bone tumors

The content of receptors for the epidermal growth factor and estrogens is studied in primary human bone tumors: osteogenic sarcoma, chondrosarcoma, malignant fibrous histiocytoma, and giant cell tumor. In all of these tumors, radioligand analysis reveals receptors for epidermal growth factor in the membrane fraction and receptors for estrogens in the cytosolic fraction without any statistical differences in the mean receptor content. The vast majority of osteogenic sarcomas, chondrosarcomas of the 2nd–3rd degree of anaplasia, and one third of giant cell tumors are characterized as growth factor receptor-positive and estrogen receptor-negative, which probably reflects the common tendency of receptor-positive malignant tumors towards rapid growth. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 78–82, July, 1996     

EFR-like peptides and their receptors as prognostic factors for the survival of patients with non-small-cell lung cancer

The levels of EGFR and its ligands have been assayed in tumor and adjacent lung tissues in NSCLC patients. Both EGFR and EGF-like peptides were found in tumor more frequently than in unaltered tissue. It was shown (Kaplan-Meyer) that simultaneous expression of EGFR and its ligands in tumor and adjacent lung tissues was associated with lower overall and relapse-free survival in NSCLC patients.     

20-year experience with continuous endocardial stimulation of the heart

Twenty years' experience with continuous endocardial stimulation of the heart is summed up. The bulk of the reviewed data falls to the period of 1980 through 1985, when 1776 primary implantations were performed, whereas more than 3,000 implantations have been performed in the past 6 years. Opinions are voiced on many aspects related to endocardial stimulation. Endocardial application of electrodes is believed to be the principal method, while myocardial stimulation should only be done simultaneously with heart surgery. Electrode application via puncture is discussed with special reference to its advantages (possible application of two electrodes at once, small cosmetic defect) and possible side effects. The results obtained with a borer electrode, designed by the authors, are reported (130 cases). Complications associated with developing rhythm competition are discussed. It is proposed that the manufacture of asynchronous pacemakers be limited considerably, and that they should mostly be implanted in cases of clinically manifest myopotential inhibition.