Inhibitory activity of luteinizing hormone-releasing hormone on tumor growth and progression.

Luteinizing hormone-releasing hormone (LHRH) is the key hormone in the control of reproductive functions. In recent years, it has become evident that LHRH might act as a growth modulatory factor in tumors of the reproductive system. We have shown that in prostate cancer cells LHRH is expressed, together with its receptors, to negatively regulate cell proliferation. In these cells, LHRH acts as an antimitogenic factor through the activation of the Gi-cAMP intracellular signaling pathway. More recently, we investigated whether an LHRH-based autocrine system might also be expressed in tumors that are not classically related to the reproductive tract, such as melanoma. Malignant melanoma is known to be characterized not only by a high proliferation rate, but also by an aggressive metastatic behavior. We have demonstrated that both LHRH and LHRH receptors are expressed in human melanoma cells (BLM and Me15392). Activation of LHRH receptors by means of a potent LHRH agonist (Zoladex) significantly inhibited cell proliferation. The LHRH agonist also reduced the ability of melanoma cells to invade a reconstituted basement membrane (Matrigel) and to migrate in response to a chemotactic stimulus. These data indicate that: (a) in prostate cancer cells the LHRH receptor is coupled to a Gi-cAMP signal transduction pathway; (b) LHRH and LHRH receptors are also expressed in tumors that are not classically related to the reproductive system, such as melanoma; in melanoma cells, LHRH might act as an inhibitory factor on both cell proliferation and metastatic behavior. It is suggested that, in melanoma, LHRH receptors might represent a diagnostic marker and a possible molecular target for new therapeutic approaches for this pathology.

An acardiac acephalic monster.

A case of an acardiac acephalic monster is described, and the literature concerning the incidence, classification and etiology of acardia is reviewed. Acardia is a very rare congenital anomaly occurring in less than 1 in 34600 deliveries. The acardiac monster has been reported only in multiple, monochorionic pregnancies. This bizarre anomalous fetus is sustained in utero by parasitic anastomoses to the circulation of its usually normal co-twin and is therefore not compatible with extrauterine survival. Possibilities for prenatal diagnosis and complications during pregnancy and delivery are considered.

A case of acardiac anomaly in the cynomolgus monkey (Macaca fascicularis): a complication of monozygotic monochorial twinning.

A case of acardius acephalus in a Macaca fascicularis is reported. This congenital anomaly occurs only in multiple-birth gestations (most commonly monozygotic twins). Artery-to-artery and vein-to-vein anastomoses appear to be a constant feature. This condition is very rare in man and probably even more so in monkeys. Classification and theories on etiology are discussed.

Radioimmunoassay (RIA) for prostatic acid phosphatase in patients with prostatic carcinoma.

In recent years radioimmunological measurements of prostatic acid phosphatase have been proposed for the diagnosis, follow-up and prognosis of prostatic carcinoma. The possibility of screening male populations at risk has even been suggested. The present paper deals with the current position of this method. We studied the specificity and sensitivity of the radioimmunoassay (RIA) for prostatic acid phosphatase in three groups of patients: a normal population, patients with benign prostatic hyperplasia, and patients with untreated prostatic carcinoma. The conclusions of this study are that the RIA is a specific method but the sensitivity is much too low to use the RIA for diagnosis and screening of patients. Comparison with the enzymatic method indicates that under good laboratory conditions the latter is preferable except for patients with metastatic disease and normal enzymatic acid phosphatases.