We describe a simple, rapid, and sensitive procedure for measuring dopamine-β-hydroxylase activity in human blood. The assay is based on the enzymatic conversion of tyramine to octopamine [1-(p-hydroxyphenyl)-2-aminoethanol], which is then oxidized to p-hydroxybenzaldehyde and determined photometrically. Activities are assayed on 2-20 µl of human serum or plasma obtained from fingertip blood samples. The method should prove useful in clinical studies, including the field of pediatrics.

Recent medical treatment of Parkinson's disease (PA) has been focused mainly on how to compensate dopamine (DA) deficiency in the striatum efficiently by using L-DOPA with/without peripheral DOPA-decarboxylase inhibitor. Norepinephrine (NE) has been also known as lowered in parkinsonism since start of pharmacological study around 1960. Marked decrease of dopamine-~3-hydroxylase

An active compound was found by sys-OF ANTIBIOTICS MAY I960 system is thought to be the cause of the hypotensive effect.

Adriamycin (ADR) is effective against a wide range of human neoplasms. However, its clinical use is compromised by serious cardiac toxicity, possibly through induction of peroxidation in cardiac lipids. Ascorbic acid, a potent antioxidant, was examined for effect in reducing ADR toxicity in mice and guinea pigs. Ascorbic acid had no effect on the antitumor activity of ADR in mice inoculated with leukemia L1210 or Ehrlich ascites carcinoma, but it significantly prolonged the life of animals treated with ADR. ADR elevated lipid peroxide levels in mouse heart, and ascorbic acid prevented the elevation. The significant prevention of ADR-induced cardiomyopathy in guinea pigs by ascorbic acid was proved by electron microscopy. Ascorbic acid and the derivatives may delay general toxicity of ADR and also prevent the cardiac toxicity. The results also suggest the clinical efficacy of the combined treatment of ADR and ascorbic acid or the derivatives.

A novel member of the epidermal growth factor (EGF) family, the neural- and thymus-derived activator for ErbB kinases (NTAK), has been purified and cloned. Five alternative spliced isoforms have been detected in the rat adrenal pheochromocytoma cell line, PC-12 cells. The rat NTAK alpha2a isoform exhibits 94% identity in its primary sequence with the human NTAK alpha isoform. In vivo, NTAK is only expressed in the brain of rat E11.5 embryos, and in the brain and thymus of adult rats. The soluble 46 kDa form binds directly to ErbB3 and B4, but not to ErbB1 or B2. NTAK, however, transactivates ErbB1 and B2 via heterodimerization with ErbB3 or B4. NTAK stimulates the differentiation of MDA-MB-453 cells and competitively inhibits the binding of [125I]neuregulin to these cells. In addition to these neuregulin-like properties, NTAK exhibits limited structural homology to neuregulins in the immunoglobulin (Ig)-like, EGF-like, and hydrophobic domains. Thus, NTAK appears to be a new member of the EGF family displaying neuregulin properties.