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In the development of novel immune therapies for high-risk cancers, one goal is to find tumor targets that are not widely shared by normal cells. One such target is the surface disialoganglioside GD2. This antigen is expressed on the surface of a variety of tumors for which no curative therapies exist for patients with advanced disease. In childhood, the most common GD2-expressing tumor is neuroblastoma. GD2 is also expressed on several other high-risk tumors, including those of neuroectodermal or epithelial origin, virtually all melanomas, and approximately 50 of tumor samples from osteosarcoma and soft-tissue sarcomas. Because of the tumor-selective expression of this molecule, it is an attractive target for tumor-specific therapies such as antibody therapy. Over the last 2 decades, several anti-GD2 antibodies have been developed. To reduce both the toxicity of the antibody and the development of human anti-mouse antibodies (HAMA), research efforts have primarily focused on exploring anti-GD2 antibodies that have progressively more human elements while at the same time reducing the mouse components. This review will examine antibodies currently undergoing clinical testing as well as the most recent advances to improve antibody therapy for patients with GD2-expressing tumors.

Chicks fed betaine supplemented diets and infected with Eimeria acervulina and Eimeria maxima had markedly higher levels of betaine in the duodenum and mid-gut than unsupplemented, infected chicks. Uninfected chicks fed betaine exhibited almost twice the levels of betaine in the gut as infected chicks. Plasma betaine levels were lower in E. maxima-infected chicks than in E. acervulina-or Eimeria tenella-infected chicks. Betaine supplementation reversed the decrease in weight gain in E. maxima- infected chicks but had no effect on the decrease in weight gains in E acervulina- and E. tenella-infected chicks. Coccidia-infected birds on normal diets regularly exhibit increases in plasma NO 2 +NO 3. This increase was abolished in E.tenella-infected birds on betaine supplement. Betaine feeding did not alter this effect in E. acervulina- and E. maxima-infected birds. Results indicate that betaine supplementation has a positive effect on gut betaine levels in birds infected with E. acervulina and E. maxima. In all treatment groups, infection lowered the levels of betaine.

Three experiments were used to test the applicability of the aromatization hypothesis of androgen action to aggressive behaviour among Norway rats. In Expt 1, administration of testosterone propionate was highly effective in restoring aggressive behaviour to castrated rats while 17β-hydroxy-5α-androstan-3-one was of intermediate effectiveness. Of the steroids tested in Expt 2, androstenedione and testosterone were highly effective, 17β, 19-dihydroxyandrost-4-en-3-one was of intermediate effectiveness and cholesterol was ineffective. The results of Expt 3 indicated that treatment with testosterone or oestradiol both resulted in increased aggression while treatment with (5α, 17β)-17, 19-bis(acetyloxy)-andostan-3-one diacetate (5α-19-hydroxytestosterone) was without effect. Androgens which were aromatizable and could be 5α reduced, i.e. testosterone, testosterone propionate and androstenedione, were highly effective in restoring aggressive behaviour; however, two other steroids, 5α, 19-hydroxytestosterone which is 5α reduced, and 19-hydroxytestosterone, which can be aromatized, were respectively of low or medium effectiveness on behaviour. However, oestradiol, which did not maintain sexual development of accessory glands, was highly effective in the restoration of aggressive behaviour. Since the behaviourally active steroids in the present experiments were not only those predicted by the aromatization hypothesis, it is proposed that several steroids are capable of activating aggressive behaviour and that the aromatization hypothesis does not adequately explain the hormonal basis of aggressive behaviour among Norway rats.

Female ring doves secrete gonadotrophic hormone in response to courtship behaviour of the male. This investigation was concerned with the quantitative relationship between the courtship stimulation presented to females and the responses of their reproductive systems. In a first experiment the degree of female reproductive tract development was found to be correlated with the length of time of daily exposure to a courting male. In a second experiment exposure time was held constant and the amount of courtship presented to females was varied by using different programmes of stimulation by males. Here too, the degree of female reproductive tract development was correlated with the amount of daily courtship behaviour presented. It therefore appears that in the female ring dove secretion of gonadotrophin is graded in accordance with the amount of courtship behaviour perceived by her.

DR. SMITH ROSE, in his letter on this subject in NATURE of September 19, has directed attention to the striking discrepancy between theory and experience in the matter of coastal refraction of wireless waves. It may be of interest to point out that the conclusion, to which he is led from Zenneck's analysis, that waves travel with a greater effective velocity the lower the conductivity of the surface, though contrary, I believe, to what is now generally accepted, is supported by quite simple reasoning.

IN a letter in NATURE of April 7, Dr. Rolf makes some very interesting comments on the subject of absorption of wireless waves by trees, and refers to a paper in which I directed attention to this phenomenon. It is quite clear, as Dr. Rolf points out, that the capacity effect of the tree ought to be taken into account as well as its conductivity effect. It appears to me, however, to be a little doubtful whether such a simple modification of Sommerfeld's theory as Dr. Rolf proposes, is all that is required. The constants of conductivity and S.I.C. employed by Sommerfeld are for an isotropic medium, whereas used in connexion with trees they refer only to the vertical axis. Again, if we increase the conductivity of the tree we clearly increase the energy absorbed, and therefore the attenuation will be greater, whereas by Dr. Rolf's method, an increase of the conductivity leads to the opposite conclusion.