Sex-linked lethal mutations induced in Drosophila melanogaster by 7,12-dimethylbenz[a]anthracene

One of the most potent carcinogens, 7,12-dimethylbenz[a]anthracene (DMBA), was tested for the induction of mutations in 2 strains of Drosophila melanogaster. Larvae were fed mixtures containing DMBA, peanut oil and solubilizing agents in darkness. After emergence the males were mated with Basc or FM7a females to test for sex-linked lethals. For Canton-S males, all DMBA treatments produced highly significant increases in mutation frequencies over controls. DMBA was slightly mutagenic for Oregon-R males.     

Serum FSH, LH and testosterone in the male rhesus following prostaglandin injection.

Adult male rhesus were treated with PGE2, PGF2 alpha or the 13,14-dihydro-15-keto metabolite of PGE2 in a randomized crossover design. Serum concentrations of FSH, LH and testosterone were determined and compared to the respective values in the same uninjected animals. No significant changes were noted in controls or following the metabolite injection. FSH increased gradually for 4 hours after metabolite treatment. In contrast, injection of PGF2 alpha was followed by an abrupt (within 15 minutes) increase in LH and testosterone. FSH increased gradually in 2 of 3 treated animals. Injection of PGE2 was followed by a similar abrupt increase in LH concentration. This was not always associated with a significant increase in testosterone or FSH. These results demonstrate that injections of PGE2 or PGF2 alpha can change serum gonadotropin and testosterone concentrations in male rhesus monkeys, and that the effects of these two prostaglandins are qualitatively different.     

Solar-driven chemical energy source for a Martian biota

Microorganisms deep in the Martian soil could derive energy indirectly from the sun via chemical reactions involving atmospheric photolysis products of the solar ultraviolet flux. The Viking discovery of a chemically uniform regolith which, though poor in organics, is rich in sulfur-containing compounds suggests reaction sequences in which sulfur is recycled through reduced and oxidized states by biologically catalyzed reactions with photochemically-produced atmospheric constitutents. One candidate reaction, reduction of soil sulfate minerals by molecular hydrogen, is already exploited on earth by bacteria of the ubiquitous and tenaciousDesulfovibrio genus.     

Influence of dietary Ca, Mg, and P on cyclic-AMP excretion and kidney calcification in the rat.

A series of five experiments was conducted with young male albino rats to investigate effects of various levels of dietary Ca, P and Mg on urinary cAMP excretion and kidney calcification. Urinary cAMP excretion was shown to be directly correlated with injected parathyroid (PT) hormone dose level and to be inversely associated with dietary Ca intake. Thus, cAMP excretion may be presumed to reflect PT activity in the young rat. Magnesium deficiency tended to reduce cAMP excretion, while P excess did not affect it. Each treatment induced kidney calcification. Calcium deficiency increased cAMP excretion irrespective of Mg status, although nephrocalcinosis appeared only in the Mg-deficient animals. These data support the view that nephrocalcinosis of dietary origin in the rat is not mediated by increased PT activity.     

Cost of management of patients with haemophilia.

The cost of managing 114 adult haemophiliacs in the west of Scotland was assessed for the period 1 March 1971 to 28 February 1974. Altogether 23 of them (20%) accounted for 80% of the resources used. The cost of hospital treatment of these patients during the period was compared with the predicted cost of home treatment, given the availability of freeze-dried factor VIII concentrate in sufficient amounts. We calculate that adequate on-demand home treatment would cost only 16% more than the present treatment, which is substantially less efficient.     

Attempts to determine the status of electroshock-induced attack in male laboratory mice

An attempt was made using a combination of simple experimental manipulations and videotape recorder (VTR) analysis of bite targets employed to determine whether electroshock-induced attack on anosmic opponents in laboratory mice was an offensive or a defensive behaviour. VTR analysis suggested that ventral surface biting was more evident in this form of attack than in social conflict. Individually- and group-housed males showed similar levels of fighting on exposure to electroshock, but dominant males from pairs showed greater attack than their subordinate partners. Zinc sulphate-induced anosmia, 36 h of food deprivation, castration and lithium chloride treatment reduced electroshock-induced attack. Although significant changes were not obtained, there was some evidence that acute treatment with dexamethasone or ACTH augmented this behaviour. The direction of these changes is similar to that seen with social conflict, and it is suggested that electroshock-induced attack in the mouse (unlike the rat) is largely an aggressive offensive behaviour. The high incidence of ventral surface biting may be a consequence of the upright postures assumed on subjecting the animals to electroshock.