Effects of high-LET particles (40A) on the brain of Drosophila melanogaster

To investigate the effects of galactic heavy particles on nervous tissue, Drosophila melanogaster flies were exposed to 40A from the Super-HILAC accelerator at the Lawrence Berkeley Laboratory. The energy of the particles reaching the Drosophila neurons was 4-8 MeV/nucleon, and the fluence ranged from 6 X 10(4) to 8 X 10(7) particles/cm2. Thirty-five days after irrdiation at the higher fluences, extensive tissue fragmentation and cysts were found. At fluences as low as one hit/two cell bodies (about 5 X 10(6)) and one hit/90 cell bodies (about 9 X 10(4) particles/cm2 or 21 rad average dose) swelling of neuronal cytoplasm and focally fragmented membranes were noted; at fluences ranging from one hit/six to one hit/135 cell bodies, there was frequently a marked increase in glial lamellae around nerve-cell processes, which often had degenerative features. These findings support the view that single hits by heavy particles may injure nervous tissue.

A fine structural study of degenerative changes in the dorsal column nuclei of aging mice. Lack of protection by vitamin E

The dorsal column nuclei of young, old, and vitamin E-supplemented old mice were examined by light and electron microscopy. Evidence of neuroaxonal dystrophy (NAD) was found in young (3-mo.-old) mice and increased with age. Vitamin E, added to the diet in the amount of 0.3%, did not protect the nuclei from age-associated degeneration. The NAD was characterized by enlarged profiles containing patches of smooth reticular networks and groups of vesicles. Various stages of mitochondrial alteration, producing multivesicular bodies as intermediate stages, were found, and other unusual forms of dense bodies were also observed. Axons, synaptic terminals, and possibly glial cells were affected, and, by 23 mo. of age, a large number of nerve fibers in nucleus gracilis were dystrophic, while nucleus cuneatus was affected to a lesser extent.

The effects of cosmic Particle radiation on pocket mice aboard Apollo XVII: V. Preflight studies on tolerance of pocket mice to oxygen and heat. Part I. physiological studies

Tests were carried out on pocket mice to ascertain their tolerance to elevated oxygen pressures alone and to a combination of hyperoxta and heat in excess of that expected during the flight of the mice on Apollo XVII. the mice withstood oxygen partial pressures up to 12 pst at normal room temperature (24 degrees C, 75 degrees F) over a period of 7 days. A few mice previously exposed to increased PO2 died in the course of exposure to an oxygen pressure of 10 pst or 12 psi (517 mm or 620 mm Hg) for 13 d in ambient heat of 32 degrees C (90 degrees F). Supplemental vitamin E and physiological saline loading given prior to exposure had no apparent protective effect. The overall conclusion was that the pocket mice which were to go on Apollo XVII could readily survive the ambient atmosphere to which they would be exposed.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: IX Results of examination of the nasal mucosa

The olfactory epithelium, but not the nasal respiratory epithelium, of the four pocket mice (Perognathus longimembris) that survived their flight on Apollo XVII showed both diffuse alterations and numerous disseminated focal lesions. The olfactory mucosa of the mouse that died during flight was also affected, but to a minor degree insofar as could be determined. All this was in contrast to the normal appearance of the olfactory mucosa of the numerous control animals. A number of possible causes were considered: systemic or regional infection; inhaled particulate material (seed dust); by-products from the KO2 bed in aerosol or particulate form; gas contaminants originating in the flight package; volatile substances from the dead mouse; weightlessness; and cosmic ray particle radiation. Where feasible, studies were conducted in an effort to rule in or rule out some of these potentially causative factors. No definitive conclusions were reached as to the cause of the lesions in the flight mice.

Effects of exygen-nitrogen (1:1) at 760 Torr on the life span and fine structure of Drosophila melanogaster

Exposure of Drosophila melanogaster adult males to an atmosphere of O2-N2 (1:1) at 760 Torr resulted in a marked reduction of life span. Among the fine structural changes occurring in the oxygen-poisoned flies, the following were similar to age-related changes: ceroid-lipofuscin accumulation in the visceral organs, sponginess of the brain and accumulation of lamellated dense bodies in the nerve cells. Also, the oxygen-poisoned flies showed a loss of the cytoplasmic membranes of the sperm cells, an alteration which was previously found in y-irradiated, but not in normal senescent, flies. In our opinion, oxygen poisoning of Drosophila may provide a valid model of accelerated aging, at least in regard to peroxidation injury of cell organelles and ceroid-lipofuscin accumulation.

A mathematical analysis of the mortality kinetics of Drosophila melanogaster exposed to gamma radiation

A mathematical model with nonlinear time-varying characteristics has been developed which describes the relationship between the kinetics of natural aging and radiation-induced delayed mortality. Based on this model, it appears that there is an immediate effect of radiation which is continuously, but nonlinearly, increasing in severity. Two phases appear in this variation, corresponding to the two phases (plateau and dying phase) of the mortality curves for control populations. Accordingly, S/E (survival time post-irradiation/further expectation of life) can best be interpreted as an increasing function during the plateau phase of normal mortality curves, which levels off during the ensuing dying phase.

An electron microscopic investigation of age-dependent changes in the flight muscle of Musca domestica L

The thoracic flight muscle from adult male NAIDM house flies was examined, from emergence to very old age. Thin sections stained with uranyl acetate and bismuth showed no myofibrillar or mitochondrial degeneration from 1 day to 19 days post-emergence, contrary to earlier reports. Some progressive loss in glycogen content and increase in mitochondrial size were observed for muscle from young to very old flies. However, there was no conclusive evidence of fusion of smaller mitochondria into larger ones with advancing age, despite exhaustive examination of representative sections of muscle samples of adult males of different ages.

Glycogen and phosphorylase activity in rat brain during recovery from several forms of hypoxia

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