[Prognostic significance of thallium-201 scintigraphy in patients with previous myocardial infarct]

With the purpose of ascertaining the predictive value of residual myocardial ischemia, in stable clinical conditions at a distance after myocardial infarction, on the incidence of late cardiac events, we evaluated 55 patients 24.2 +/- 11.4 months after myocardial infarction with thallium-201 stress test imaging. All patients were either asymptomatic or with stable effort angina pectoris, well controlled with medical treatment. In the next follow-up period, whose duration has been 22.4 +/- 14.4 months, the incidence of unfavourable cardiac events, like unstable angina, reinfarction, coronary bypass surgery, sudden cardiac death has been monitored. Thirty-one patients (56.4%) presented a reversible perfusion defect (RPD) in one or more myocardial segments; 17 of these 31 showed cardiac events during follow-up. Only 2 patients of the remaining 24 without RPD had cardiac events, with a significant difference (p less than 0.01). The patients with RPD only in peri-infarct areas had a relatively smaller number of cardiac events, with respect to those patients with RPD also or only in distant areas. Fifteen of 21 patients with RPD in 2 or more segments manifested cardiac events, compared to 2 of 10 patients with RPD in only one segment (p less than 0.01). In 10/55 patients, increased lung uptake of thallium-201 activity was observed; 8 of them presented cardiac events (p less than 0.01). This analysis confirms the high predicting value of thallium-201 RPD imaging on the incidence of cardiac events in patients controlled at a distance after myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

[Breast carcinoma. Technical problems of radiotherapy. Proposal of an algorithm as an alternative to the lack of scintigraphic visualization of the internal mammary lymph nodes]

In early breast cancer, radiation therapy following conservative surgery needs a topographic evaluation of internal mammary lymph nodes. Three-dimensional lymphoscintigraphy (IML3D) is an useful method for this purpose. The average depth of the lymph nodes is closely correlated with the square root of the body weight/height ratio. We calculated the individual maximum depth of the lymph nodes from this function; the parameter was then verified with the experimental data from our series of cases (53 patients). Although the suggested algorithm needs to be verified on a larger number of patients, we believe the empirical maximum depth measurement to be useful when IML3D is unfeasible or the internal mammary lymph nodes are not demonstrated on scintigraphic scans.

[A case of AIDS-related complex (ARC/LAS) in a health worker]

A case of ARC/LAS syndrome in a student nurse accidentally pricked by an infected needle is reported. This case-report is published to encourage the recognition of hospital staff.

Intrinsic and extrinsic factors in estrogen action in human breast cancer: role of polyamines and pituitary factors

Although polyamines are important in regulating proliferation of mammalian cells, their role in hormone induction of cell growth has not been delineated. In the estradiol-responsive human breast cancer cell line, T-47D clone 11, estradiol (10(-10) M) was able to stimulate cell proliferation and the activity of ornithine decarboxylase (ODC), the first and rate-limiting enzyme in the biosynthesis of polyamines. alpha-Difluoromethylornithine (DFMO), a specific inhibitor of ODC, blocked the estradiol-induced cell proliferation and ODC activity. Exogenous addition of putrescine, the natural product of ODC, rescued the inhibitory effect of DFMO. In addition, DFMO abolished the estradiol-induced growth of several other estrogen-responsive human breast cancer cell lines but did not affect the growth of hormone-independent cell lines. Further, a serum factor was found to be required for estradiol to exert its effect. To gain insight into the nature of this and possibly other extrinsic factors involved, the effect of estradiol on the proliferation of T-47D cells transplanted into athymic nude mouse was evaluated. In this in vivo system, estradiol alone produced only moderate growth of the human breast tumor. The simultaneous transplantation of a prolactin (PRL)- and growth hormone (GH)-secreting rat pituitary tumor or normal rat pituitary glands at a different site dramatically potentiated the effect of estradiol on the growth of the breast tumor xenograft. Purified PRL or GH were without effect, indicating that the active pituitary factor is neither PRL nor GH. Further, conditioned medium from rat pituitary tumor cells potentiated the mitogenic effect of estradiol on T-47D and several other estrogen receptor-positive human breast cancer cell lines in vitro under serum-free condition. In conclusion, we have identified both intrinsic (polyamines) and extrinsic (pituitary/serum) factors that are importance for estrogen to exert its mitogenic action. The next goal will be to elucidate the mechanisms of action of these molecules in the modulation of estrogen action.

Role of polyamines in estradiol-induced growth of human breast cancer cells

The present study explored the possible involvement of polyamines in estradiol-stimulated proliferation of human breast cancer cells using the estrogen-responsive subline of T-47D cells (clone 11). 17 beta-Estradiol (10(-10) M) stimulated cell growth 2- to 4-fold. This estradiol-induced proliferation was associated with a peak (at 12-24 h) of activity of ornithine decarboxylase (ODC), the first and rate-limiting enzyme of polyamine biosynthesis. Estradiol-induced cell growth and ODC activity were observed only in the presence of 10% charcoal-treated fetal bovine serum, suggesting that serum factors are required for estrogen action. alpha-Difluoromethylornithine (DFMO, 0.1 mM), a specific inhibitor of ODC, blocked the estradiol-induced cell proliferation and ODC activity. Putrescine (0.1 mM) rescued the inhibitory effect of DFMO on growth of steroid-treated cells. Putrescine alone was not stimulatory to cells, and in combinations with estradiol, it did not augment the effect of estradiol. In addition, DFMO abolished the estradiol-induced growth of several other hormone-responsive cell lines but did not affect the proliferation of unresponsive cells. Hormone-responsive cells exhibited differential sensitivity to DFMO; resistant cell lines (e.g., MCF-7) were found to possess higher endogeneous levels of ODC than sensitive cell lines (e.g., T-47D and ZR-75-1). Our findings indicate that polyamines are essential, although not sufficient, in estrogen stimulation of human breast cancer cells.