Loss of a Harvey ras allele in sporadic Wilms' tumour

Genomic changes within chromosome band 11p13 appear to have a role in the initiation of Wilms' tumour. The human Harvey ras oncogene, c-Ha-ras 1, has been located by Jhanwar et al. immediately adjacent to this region at band 11p14 .1, although several groups have assigned the gene more distally at band 11p15 . We have examined tumour DNA from two cases of sporadic Wilms' tumour, and report here that in both cases one of the two constitutional c-Ha-ras 1 alleles was absent. One tumour had a reciprocal translocation between the short arm of chromosome 11 (at band 11p13), and the long arm of chromosome 12, with no visible loss of chromosomal material. The loss of a c-Ha-ras 1 allele in association with this translocation indicates that a submicroscopic deletion had occurred. The resulting hemizygosity may have had a role in tumour initiation. Our results indicate that the c-Ha-ras 1 gene and the 'Wilms' tumour locus' may be in close proximity. It would, therefore, be premature to exclude the possibility that these two sites are functionally related.     

Effect of 5-hydroxytryptamine antibodies on pigment migration in the erythrophores of the fiddler crab,Uca pugilator: Further evidence for 5-hydroxytryptamine as a neurotransmitter that stimulates release of red pigment-dispersing hormone

Summary 5-Hydroxytryptamine (5-HT) antibodies inhibit red pigment dispersion in the fiddler crab,Uca pugilator. This observation supports the hypothesis that 5-HT stimulates release of red pigment-dispersing hormone.The 5-HT antibody preparation was a generous gift from Dr S. Spector, Roche Institute of Molecular Biology, Nutley, New Jersey.     

Stereoselectivity in mammalian chemical communication: Male mouse pheromones

Two male mouse pheromones, 3,4-dehydro-exo-brevicomin (DHB) and 2-sec-butyldihydrothiazole (SBT), are chiral molecules which were previously tested in their respective bioasays as racemic mixtures. The focus of this study has been to determine the absolute configuration of their natural forms and its relation to stereospecific biological action. DHB was established as the R,R-enantiomer possessing biological activity. Due to an extremely easy racemization of SBT under very mild conditions, enantioselectivity of its transmission and its action at the receptor site appear to be of secondary importance.     

Effect of different bathing media on the short-circuit current across the intestine of the rat and guinea-pig

Summary The changes in short-circuit current occurring when one or both solutions bathing the intestine of rat or guinea-pig mounted in flux chambers were recorded. The results with the guinea-pig can be explained in terms of diffusion potentials arising from the ionic replacements, and an electrogenic sodium pump, sensitive to ouabain, in the contraluminal membrane of the cell. In the rat, the situation is more complicated, and the enterocyte probably possesses an electrogenic sodium pump in the brush-border membrane.     

Melatonin antagonizes colchicine-induced mitotic arrest

Summary Melatonin, in concentrations up to 10^–3 M, showed no effect on mitosis in cultures of HeLa or KB cells. However, when melatonin at 10^–4 M was preincubated with HeLa cells prior to addition of 10^–7 M colchicine, a reduction in the mitotic index, in comparison to colchicine alone, was observed.This work was supported by PHS Grant No. CA 16425.     

Effect of gum Arabic on aminopyrine demethylation in rats

Summary Stimulation of aminopyrine demethylation induced in rats by oral or i.p. administration of phenobarbital was partially inhibited in animals receiving daily treatments of 2×200 mg/kg gum Arabic p.o.     

Retroviral antigens on gs- chf- leukocytes

It has recently been suggested that the endogenous retroviruses present in many different species might be involved during stimulation of the immune system of their hosts. We have now studied the expression of two avian retroviral antigens p27 and gp85 in chicken lymphoid cells by indirect immunofluorescence (IIF) and by complement-dependent microcytotoxicity (CDM). We have now found that these viral antigens are expressed in peripheral blood leukocytes of adults and embryos and in splenic and bursal lymphocytes of Spafas gs- chf- chickens but they are not expressed in fibroblasts cultured from the feather follicles of the same individual adult birds nor in fibroblasts cultured from embryos of the same flock. The differential expression of viral antigens in leukocytes may be related to a specific property or function of these cells.